How to Laminate Large Composite (Fibreglass) Moulds

►Full Project Guide: www.easycomposites.co.uk/lear...
Further information and links ▼
Second video in a four-part series following a project to make lightweight, super tough sledges for a polar world-record attempt. Introduction to the project here: • The Dark Ice Project I...
In this tutorial we demonstrate the correct method for laminating larger composite moulds using our Uni-Mould rapid tooling system. The method shown allows a single laminator to lay-up a mould of almost any size. The tutorial covers suitable pattern materials and coatings, release agent application, gelcoat application, coupling/tie-coat application and the main layup.
Products featured in this tutorial:
►Complete Uni-Mould Kits www.easycomposites.co.uk/uni-...
►Uni-Mould Tooling Resin www.easycomposites.co.uk/uni-...
►Uni-Mould Tooling Gelcoat www.easycomposites.co.uk/uni-...
►Uni-Mould Coupling Coat www.easycomposites.co.uk/uni-...
►Emulsion Bound CSM www.easycomposites.co.uk/450g...
►Easy-Lease Release Agent www.easycomposites.co.uk/easy...
►Lint Free Wipes www.easycomposites.co.uk/lint...
►Filleting and Filling Wax www.easycomposites.co.uk/soft...
►Filleting Tools www.easycomposites.co.uk/Ball...
►Laminating Brushes www.easycomposites.co.uk/comp...
►Plastic Finned Roller www.easycomposites.co.uk/plas...
►Plastic Demoulding Wedge www.easycomposites.co.uk/plas...
►Blue Polishing Pad www.easycomposites.co.uk/medi...
►NW1 Cutting Compound www.easycomposites.co.uk/nw1-...

[@ASCENDANTGAMERSAGE]

I understand this is marketing, but it's marketing done well. I'm voluntarily watching an ad and enjoying it a lot. Great job y'all.

[@easycompositestv]

Thanks Sage, we are indeed a business and we do need to sell our products in order to pay for making this content but we do our best to make it as broadly relevant as we can and I think we get the balance right. Thanks for watching.

[@kalujny]

To be fair its at least half and half instructional video / ad. And the tutorial part is excellent.

[@crowdozer3592]

carbon fiber has always been a bit of a "dark art" to me, I assumed it was super complex wizardry that the ordinary person couldn't do, but you guys have completely cleared that illusion and these are some of the best informational videos (of any craft) on youtube. I don't live in the uk but if I end up ordering materials to try it out myself, definitely going to go through you guys 😄

[@easycompositestv]

Thank you, appreciate your comments and your future support :)

[@KirtFitzpatrick]

That mold looks amazing. This mold making process so far has kinda blown my mind. Excellent work.

[@SeanOBryanZZ]

Can't wait to see this thing in use! Definitely need a before and after on the gear

[@adambournes8356]

The best fiberglass layup videos on the internet. Great detail. Lots of "tribal knowledge".

[@ww07ff]

Can't wait to watch the next episode! Best regards from Brazil!

[@CanineDefenseTechnologies]

I was hosnetly afraid of getting into composites. Your company's presentation and knowledge really helped me to get started and I'm having a lot of fun! I really like the thorough and clear explanation!!

[@easycompositestv]

Thank you very much; it's fantastic to hear that we may have helped get you started in composites and that you're enjoying it :)

[@crazytrutas]

I second that. thank you for the uploads.

[@cerb345]

likewise, although im getting shivers from that loose strand hell during the layup of the 450g mat. clean up looks awful

[@snorttroll4379]

@@easycompositestv is the special resin for the gelcoat important so I can use polyester and epoxy?

[@timpickering253]

Love these video tutorials, I learn something new every time. Cheers Easy Composites.

[@easycompositestv]

Thank you Tim

[@lattitude01]

Not going to lie, i jumped into this video randomly via youtube's chain of random videos, skipped to about half way in and i spent nearly the entire video from then on under the impression you were making a custom bathtub xD. Lovely work.

[@freedomtowander]

Same!

[@krisjclark]

I hope these videos are good advertising for you, but they are also great entertainment! I'm looking forward to seeing the finished product. Unfortunately I can't buy much from you because the chemicals couldn't be shipped to Canada, but I would if I could. Your videos really helped me start and finish a project that looks amazing and it was only my first try!

[@easycompositestv]

Thanks Xavier, that’s good enough for us. We do want to encourage and support composites enthusiasts, even if it’s not easy for you to buy for us. We’re also hoping to open a branch in North America fairly soon.

[@EnglishLaw]

This channel is amazing. Exactly what I was looking for (for some time).

[@jeanfrancoispoivre4438]

Encore merci a l'équipe easy composites 😉😄

[@muumarlin1731]

Could watch these all day - amazing tutorials!!

[@easycompositestv]

We appreciate the kind comment! Thanks for watching!

[@yassinchbani4267]

Amazing work friends. Thank you for sharing.

[@easycompositestv]

Thanks Yassin, appreciated.

[@patronista]

Impressive video, thank you very much for all that you help us professionals and those of us who started in composite materials, I am currently finishing my pattern, then I will buy the unimold system to make the mold.

[@easycompositestv]

Great to hear Ernesto 👍 we look forward to hearing how you get in.

[@richardlarnach8678]

Simply the best video tutorials on this subject matter.

[@easycompositestv]

Thank you Richard, that's very kind.

[@AHustleIsLikeASideOfFries]

Yes, I'll second this. Very good production values, seemingly enough editing, well spoken yet approachable dialog, just overall excellent.

[@chuckeynewkirk199]

For sure one of the best videos for educational content!!!!

[@easycompositestv]

Thanks Chuckey! :)

[@ricardo_sarmiento]

you guys make it so easy to understand !!

[@easycompositestv]

Thanks Ricardo, we do our best, it's good to get your feedback.

[@ryanhines719]

Love these videos. Def looking forward to buying some kits and materials to try making some carbon fiber parts for my car!

[@easycompositestv]

Great stuff Ryan, look forward to working with you 👍

[@Jedermeister]

Alternative Title: How to construct a stylish, modern and lightweight black bathtub with composite materials

[@easycompositestv]

Don't forget heavily impact resistant bathtub!

[@RCONSTRUCT]

Everyone is a comedian in the comments section

[@chuckeynewkirk199]

Haha form fits function, Eskimos eat your heart out!!!

[@dennisyoung4631]

That isn’t much of a joke, as I *have* thought about making a “camping bathtub” of fiberglass. It would be perhaps four inches /10 cm deep, about 2 feet /60 cm wide, and 3 feet /90 cm long.

[@cvspvr]

@@dennisyoung4631 what the fuck is the purpose of that?

[@FerrellMcCollough]

Great job. For those that have the correct working space it's best to use a gel-coat cup gun to apply the tooling gel coat. The thickness will be uniform and to spec. This will avoid crazing in thick areas of gel and ghosting of fiberglass in thin areas after many parts are made. After gel-coat and you're ready for lay up, always put your resin down first then your mat on top, it helps eliminate air bubbles and is faster - essential for a "hot" pot of resin (meaning high % of MEKP).

[@ScrewDrvr]

Your videos never show in my sub page...always find them in recommended. Love the videos, keep'em coming.

[@easycompositestv]

Not sure why that would be but glad you found and and you’re enjoying them!

[@captivenut4122]

Same for me here.

[@user-om3jw3nj4q]

Thank you. Thank you. Thank you for making the clip. I have been waiting for a long time. Thank you very much. I have gained more knowledge.

[@easycompositestv]

You're very welcome

[@captnjaygreybeard6394]

Cool stuff, thanks

[@CmwSpeedrunUk]

Really enjoy watching your videos

[@easycompositestv]

Thank you, we enjoy making them.

[@VLXVNDR]

A well made video 👌🏼👌🏼

[@brett1nita]

Excellent and accurate tutorial. We rarely use the tooling gelcoat and tooling resin because of the cost here. I wish you had a way to supply in South Africa!

[@easycompositestv]

Thanks for your comment Brett, glad you're enjoying the tutorials. It's certainly not easy or cheap for us to ship resin products to South Africa but who knows, maybe in the future we'll have an outlet closer to you.

[@janatlmb2770]

Yet another great video, I am really keen to laminate st, but I do not know what :D I am looking forward to seeing the next episode of this sleigh.

[@easycompositestv]

Hi Jan, thanks for the comments. Glad you're enjoying the series. I'm sure you'll think of a suitable project soon enough!

[@fabricebouillaud]

an excellent video .Great job !!

[@easycompositestv]

Thanks Fabrice, appreciated.

[@shnnenluo9876]

You just did a remarkable job!

[@easycompositestv]

Thanks Shnnen :)

[@XB10001]

Very nice workmanship.

[@easycompositestv]

Thank you very much!

[@SRFirefox]

Both informative and an unobtrusive advertisement for your services and products. Well made

[@easycompositestv]

Thank you, that’s the balance we try to strike 😀

[@christippins7354]

Greatly explained 👍

[@easycompositestv]

Thanks Chris :)

[@Jmas369]

Nice video love it.

[@TurbineResearch]

Looks amazing ❤ beautiful car

[@CodingExpress]

Thank you too!

[@WickedMachineWorks]

That mould would make a great bath tub afterwards! :D

[@PaperRocket1886]

This video series beats all the one handy, shaky cam, in the basement, slapped together, filmed in 2001 mold projects tutorials I’ve seen. Pluuuus we see what groups of products work really well together.

[@easycompositestv]

Thanks, glad to hear we’re hitting the mark 👍

[@deltamangr6247]

Your company and your tutorials are one of the best there is. Do you have a reseller in Greece please?

[@easycompositestv]

Thank you. We do have one reseller in Greece called A.Andreou ; they carry a selective range of our products.

[@RockitFX1]

That's a pretty sweet bathtub!

[@eleazarruiz6047]

Gracias por estos tutorial nos perfeccionamas gracias

[@easycompositestv]

Thank you for commenting Eleazar, glad you enjoyed the video!

[@MrMcbuck48]

Good as usual

[@easycompositestv]

Cheers Frank!

[@omegaelixir]

So I started playing with carbon after seeing these vids. Ever since I started doing it, I got a lot left over fiberglass moulds. PLEASE MAKE A VIDEO ON RECYCLING. Thanks

[@tacticaltot8754]

Fiberglass is often used for it's longetivoty and durability. Impregnated fiber cannot be un-impregnated and recycled

[@MustaqimMuhammadHatta]

terimakasih sudah berbagi... 🙏🏻

[@andrey.p]

Thank you, Paul and the team involved, apart from an excellent and engaging presentation, everytime I watch your tutorials you leave me with an exciting feeling of being able to do it myself. I hope I will realise some of my ideas sometime :) Wanted to ask for long time, is it viable to straight 3d print a mould from Polyethylene?

[@easycompositestv]

Thanks for your comments Andrew, we hope you realise those ideas too. 3D printing a mould is possible but there’s lots of considerations. We’re planning a comprehensive series of video tutorials on 3D printing for composites at the moment. It will be out next set of tutorials.

[@neil2153]

The mold releasing out is the most satisfying thing to see after so much work. And the mirror polish, ooh la la.

[@easycompositestv]

Hi Tarneil, thanks. Yep, successful demoulding is one of the best parts of composites :)

[@alihho]

what a relaxing sound 12:25

[@juanrafaeltosado1812]

GREAT!!!

[@easycompositestv]

Glad you enjoyed!

[@user-fg3qn8ho8s]

Really nice. I woul like to do it. Like you

[@easycompositestv]

If you do try, please let us know how it goes or if you need any advice!

[@bobbyrollins5911]

Do you guys have any Videos where you explain how the overlay carbon fiber edges, i m trying to make a carbon steering wheel but i don't get the cut as clean as i want it to be and it's is clearly noticable.

[@betarr80]

stunning tutorial. If i have a lot of smaller parts like 5/10 small and medium mould for carpon parts is more cost effective to make all the mould with this method of swich to epoxy mould kit?

[@stevesloan6775]

How good did that plug come out of that mould..!!! 🇦🇺🤜🏼🤛🏼🍀🤓

[@juanrafaeltosado1812]

¡¡GREAT JOB!!! .

[@easycompositestv]

Glad you enjoyed!

[@tonybeatbutcher]

Some heavy professionalism !!

[@easycompositestv]

Thanks Tony :)

[@xiaosun9111]

thanks~

[@genekrafft948]

Use a long nap paint roller for wet out. Much faster, more even resin distribution and will do a lot air removal as you wet the part.

[@toddlehman928]

I also use the nap roller to soak up excess resin on my skin coat and subsequent coats, although ideally I would be using a chopper gun that I would have dialed in to 36% glass

[@bw3996]

Suddenly tempted to mould a 32 ft boat hull in my garage

[@easycompositestv]

That’s the spirit!

[@jonnysz03]

Wowsers guys! You've really knocked it out the park with these videos. Well played. I have a question about the Uni Mould system: I'm about to delve into the world of fibreglass having previously used solid, filled polyester as my primary weapon of choice to fabricate climbing holds. I'm now fabricating much larger holds that would benefit from a fibreglass construction. Typically, I'd use silicone moulds to pour into and was planning on using a relatively thin silicone mould with a fibreglass shell but having seen the Uni Mould system, I'd be more inclined to use this. However, given that the climbing holds require a textured surface, would the Uni Mould struggle to de-mould from this? If so, do you think the silicone layer/ fibreglass layer would be more beneficial? Many thanks and keep up the amazing work, Jonny.

[@easycompositestv]

A highly textured surface would be a challenge to demould on a conventional mould. The advantage of silicone is its natural release properties and the fact it can be peeled and flexed. I would probably go for a silicone mould with glassfibre jacket as you get the support of the glass to hold the shape and ease of demoulding from the silicone.

[@jonnysz03]

@@easycompositestv You're a star! Many thanks for the advice, and like I said earlier, these vids are fantastic.

[@ErtsenPlayGames]

Again avesome video with great explanation how ewerything works :) PS remember to take hot bath in it before use XD

[@easycompositestv]

Good tip, will do ;)

[@wylieecoyote]

Great job! I saw software that allowed creating a reverse image of the pattern. This can be carved and used to create the mold with fewer steps, saving time and money. Are there constraints for using that system or are you unfamiliar with it? Thanks for such a detailed tutorial showing the proper use of your products.

[@easycompositestv]

Sometimes for low volume or one off mouldings, that method can be used to carve a mould via CNC out of a high density model board directly. You can then use our S120 board sealer to make a sealed surface suitable to work from. Generally for longer production runs or for large moulds such as this, the model boards are not so practical or durable for use in that way.

[@asacabinetnsoundpune1235]

I do all this work, I make sound in sides design 🥰

[@Klaster_1]

Do you plan to make a video on cleanup, disposal and preparation? I suspect this takes significantly more time than the fun part.

[@easycompositestv]

Maybe we’ll do some more general background videos and could include some more things like this. Thanks for the comment.

[@stevenr8606]

⬆️ Maybe means NO!

[@pietzeekoe]

Looks like a nice bathtub now.

[@easycompositestv]

Yep, this thing pretty much looks like a bathtub from start to finish!

[@janatlmb2770]

my thoughts exactly? no I know how composite baths are made, at least the moulds for them :DDD.

[@Runoratsu]

@@easycompositestv you shoulda just used one as your mould then, much cheaper and less labour intensive! 🤪

[@Mchacz8008]

This is one of the most popular methods of making bathtubes btw

[@philippe-lebel]

Actually it's an "anti-bathtub" to keep the water outside (solid water by the way) ;)

[@andikhafiber]

Sehat dan sukses selalu friend Salam from indonesia

[@ExploreComposites]

That came out nice! What was the finished thickness of the mold shell? Did you consider any backing structure? I guess with that planar flange and flexible parts it probably doesn't need it...

[@easycompositestv]

Laminate thickness from these 4 plies was about 5-6mm which is typically a suitable thickness for most production moulds. We didn’t consider a backing structure for the two reasons you mention; the flange does a good job of stopping the mould from trapezing and with the part being quite flexible anyway there is little concern about keeping the mould to very exactly accuracy.

[@pranavbhor5477]

If I,m directly making a mould what clearence should I leave for all the layers of GF you specified and what should be the Fiber to resin ratio while applying GF layers also I ive in a different country so instead of uni-mould tooling resin can I use polyester resin mixed with chalk powder/any other putty. Please reply.

[@Alex-vz2jz]

Instructions unclear, i ended up with a bathtub. Jokes aside i love how simple you explain these types of video. Very useful thank you.

[@easycompositestv]

And a very strong bath tub it was, no doubt! Glad you find the videos useful.

[@Jules262]

Thank you for this incredible video! Is there by chance a variation of this fibreglass that can remain transparent after lamination?

[@easycompositestv]

Most thin fibreglass fabrics will remain semi translucent depending on number of layers.

[@crazystuffproduction]

I jsut wish you uploaded projects a little more, these are well made.

[@easycompositestv]

Thanks, we're doing our best. You'd be amazed how many days these each take!

[@mohamedelkharraz8315]

Toujour tooooop. de morroco

[@LesAventuresDeTigRRe]

Hi Do you know where I can find any good composite products in Switzerland? Your site is the greatest and your products look amazing, but the shipping cost would kill me

[@adithya_k93]

Great video as usual, So vinyl ester gelcoat is better than polyester gelcoat for epoxy infusion?

[@easycompositestv]

Yes, 100%. It’s a small change that makes a big difference. We never recommend polyester gelcoats when making moulds for epoxy components.

[@doktorscottdiabolical]

Excellent Step-By-Step video! Would callouts for average open times and cure times be appropriate to include in these videos? Or is the system too sensitive to environment temps and humidity for that?

[@easycompositestv]

Hi Scott, that’s a very good suggestion. Certainly these parameters are influenced a lot by things such as ambient temperature, size of mix etc., but they could be called out with ranges (I.e. 5-10mins). My only reservation would be to ensure they’re not too distracting but done right it could be useful. We’ll have a think!

[@doktorscottdiabolical]

@@easycompositestv Awesome! I've used polyester in July in Georgia (95 degrees, 100% humidity, 800 ft altitude) and in January in Colorado (8 degrees, 3% humidity, 5800 ft altitude). With batch sizes of 8 oz and the same catylization ratio, one had an open time of 3 minutes. The other needed 2 days and finally a heat gun just to cook off. I've also used a 4:1 epoxy that wasn't affected by the cold at all.

[@rnichol22]

Youve made a lovely bath there :)

[@V8VRUte]

And after all the sleds have been made, the mold looks like it would make a fantastic bath tub...

[@j.p.279]

marvelous, what is the difference between the first resina transparent and the white one?? here only can get the transparent... thanks guys, you're amazing

[@easycompositestv]

The tooling resin (the cream one) is packed with fillers which stop it from shrinking. This allows all layers to be laminated in one go without shrinking or distortion. There’s a full description of this and other aspects of the UniMould system on the accompanying project page on our website. Link in the description.

[@MichaelWhiteRacing]

Fantastic insightful video. Ive just bought one of you mould kits and materials to have a go at making some simple carbon parts for my race car. Id like to use originals to take a mould from but they've been painted quite poorly in rattle can satin black. Can you recommend something i can treat the parts with to allow the moulds to release once made? Thanks

[@easycompositestv]

Painted surfaces, especially 'rattle can' paints are a nightmare to work with as the solvents in the gelcoats often attack the paints and the solventing from the paint can push away the release agents creating a perfect storm for the parts not coming out of the mould. For such a part, it is often worth vinyl wrapping the part first before applying a generous coat amount of release agent to the vinyl thus guaranteeing that the mould comes away from the vinyl and the vinyl can be removed from the original part whilst creating a physical barrier between the two.

[@MichaelWhiteRacing]

@@easycompositestv Perfect thank you. I was going to ask if vinyl wrapping was a possibility.

[@denvernow7294]

When he pulled out the form and polished the mold, this looks like it turned into a diy video of how to make a sexy bathtub.

[@tkzsfen]

Watching this video without a gas mask subconsciously makes me cough and inhale all the fiber glass and epoxy...that are not in my room :D Funny, how seeing someone do something brings your experience with it on a physical level.

[@marketfluxadvertising]

Hello i wanna make mould for my aircraft engine cowling. What thing will you suggest to make the mould since i am not gonna required that mould again and again?

[@michaelwolff4152]

Where is the 3rd video? I love your content thank you!

[@easycompositestv]

The next video is here: kzbin.info/www/bejne/rYGpdXWKaZaGe7c

[@michaelwolff4152]

@@easycompositestv I was referring to the 3rd video of these sleds, showing the mould being used. However I found this video on your website!

[@easycompositestv]

@@michaelwolff4152 the final part in the series where we use the mould to make the sled is here kzbin.info/www/bejne/p36zhHyBm9CXqrM

[@andrewallason4530]

Vinyl Esther??? That was the name of my former IT systems manager’s “girlfriend “. 🤣

[@Richard-do1hb]

15 min of work for sprayup. 😉 Talon Internal mix with VRC-1000 chopper motor, it does wonders. I run an MVP MiniPro 22:1 for gelcoat and 11:1 for resin. Blades set at ~15mm fibers for skin coats and ~30mm fibers for bulking. Even solo, I can process 3 to 5 m2/hr with a very low incidence of voids, especially when coupled with a high quality radius putty. Cheers from South Carolina, USA!

[@tacticalant3841]

So you mention tearing the edges of chop strand where they will butt, but you only did it in some of the joints?

[@easycompositestv]

It's not hyper critical; when you tear the edge of chopped strand you're really just helping along with what you do with the brush anyway. As you 'stipple' the chopped strand mat it will break down, allowing you to feather the edge just with the brush. It's all preference and - at the end of the day - it's just a mould in this case.

[@cbbbbbbbbbbbb]

Do you ever find the need to vacuum out the mixed resin before applying, especially in these large quantity batches? It seems like it works well enough without a vacuum being used.

[@easycompositestv]

Careful mixing means it is not an issue. Also the resin is not especially thick so brushing on and careful rolling of the laminate is all that is needed to remove trapped air.

[@RodrigoNascimentoMattos]

why is this part diferent from the one in "how to make a large composite patter by hand"??

[@snorttroll4379]

do you have a video about making reusable vacuum bags? also what if one just uses a lot of wax layers, will the part release easily then?

[@easycompositestv]

We do not have any videos on that. The vacuum storage bags are often reusable for simple wet lay vacuum bagging work. Durability is always an issue as it only takes a small piece of fibre to pierce a bag and ruin it.

[@easycompositestv]

We don't have a video showing reusable bags no. You can build up a good release surface using layers of a wax release agent yes.

[@sivaranjans2452]

Would it be ok to give it a jet of air from a compressor after putting the wedge in during demoulding?

[@easycompositestv]

It certainly shouldn't do any harm, I guess it's more a question of whether it's necessary. This particular part released from the mould perfectly but if something was being more stubborn then compressed air can be used to help things along (particularly if you're just struggling against a static or vacuum lock).

[@sedatminer4489]

quick tips 12:07 you can drop some water it will pop the mold was easier

[@easycompositestv]

We’ve only ever used water when PVA has been used as a release agent but it’s an interesting suggestion, thanks.

[@2110FSX]

We used to use car wax on the mould, put about three to four layers of polish on the mould and it's Bobs your Uncle.

[@zip7806]

All this work and they could have just bought a Bath Tub as the mold. Ha Ha. I'm just teasing. Thanks for the informative videos.

[@hrivcxz]

Sir, some time after painting the first layer ( gel coat or resing + powder), some areas poping up between resin layer and mould, which means forming air pockets, what is the reason

[@easycompositestv]

It could be a number of issues such as too warm conditions or even pre-release of the gel from the mould surface.

[@alexbowie6316]

I love the work and the channel. Horrible dirty smelly work in polyester though.

[@matrix7730]

hi,are you sending your products outside the country or just in UK? in my case Sweden

[@easycompositestv]

We ship all over the world

[@Pushyhog]

if they would open small sales shop for their products in east coast usa would be great. North Carolina would be best.

[@easycompositestv]

Thanks Pushydog, we're working on it!

[@daytonjacobson55]

Is there a reason your not using prepreg carbon? I have been making parts using prepreg from a company in the USA but not super happy with the outcome. So this winter I'm ordering everything I need to finish a front lip for a Sema show truck. I debating on prepreg or the infusion method.

[@easycompositestv]

Spoiler alert, for this project we won’t be using carbon fibre at all but that will become more clear after the next video. As for you project, both prepreg or resin infused carbon would be totally legit; your main consideration between the two would be the mould (tool) would cost more for prepreg because it needs to be high temperature, and also you would need an over large enough to load the front lip into to cure it. Contact out tech dept. directly if you’d like to discuss the differences in more detail. We’re shipping a LOT of prepreg to customers in the States these days!

[@daytonjacobson55]

@@easycompositestv thank you! I do have a large oven since I own a powdercoating business. Also making the high temp molds was a very big pain, hated the high temp resin. (again not your brand) very excited to use your products!

[@xnadave]

A lot of the tutorials I see say to let the gelcoat cure until it's tacky before applying reinforcement. Is it a problem if it completely cures before applying reinforcement? (As in, is it okay to let it sit longer, or is there some magical thing about the gelcoat being tacky that's preferable?) I can see why you wouldn't want to apply reinforcement fabric and resin too early, but is there a "too late?"

[@easycompositestv]

Very fair question. To some extent it does depend on the gelcoat you’re using but generally whilst it is possible to be too late, this would be *many* days later. The reason for this is because polyester and vinylester gelcoats (like the UniMould Tooling Gelcoat) have a property called ‘air cure inhibition’ which means that the resin doesn’t really cure if it’s in contact with air. This is intentional so that the surface of the gelcoat stays ‘tacky’ indefinitely. So, your window for backing up a polyester or vinylester gelcoat is very long.

[@xnadave]

@@easycompositestv Interesting. That seems to make sense. I probably should've paid more attention in chemistry class. :)

[@xnadave]

@@easycompositestv (And have a great rest-of-your weekend!) Now if I could just find filleting wax in the US... clay is a bit of a pain to work with.

[@scutohugo920]

Is it possible to go with classic polyester resin for the second layer of fiberglass ?

[@easycompositestv]

You could but you would be needing to deal with the classic problem of traditional polyester resin layups, which is the shrinkage. The best way to deal with polyester shrinkage is to lay us one layer at a time and allow it to cure fully between plies. By building up the layers slowly, over a number of days, the effects of shrinkage are significantly reduced. The advantage to Uni-Mould is that its shrinkage is negligible, allowing what should take four or more days to be done in one for the same result.

[@smallnuts2]

I was wondering, with every sled, did you have to do the profiles? Or did you make a mold from the first profile sled? Im curiouse if it saves weight or structure etc.

[@easycompositestv]

This video is for the mould not the finished sled. So yes the mould can be reused many times as needed.

[@ecomarinebd]

Hi, I was wondering if I could take a large, say a bed-size piece of EPS block and laminate with epoxy to make pontoon floats for making jetties. Possible?

[@easycompositestv]

I suspect for durability reasons you would need a skin with GRP or other laminate to give it suitable strength compared to resin alone.