Making a large composite mold of complex shape. Part 4: Parting surfaces and mold-making

This is the fourth and last part of a short video series on making a large composite mold. We show how parting surfaces can be made and how our three part mold is produced using vacuum resin infusion. See last part for information on how to give the plug a high gloss finish: • Making a large composi...
#hortenmicrolight

[@jimny4k]

Just researching this process and came across this....excellent! Looks like a great family team too!

[@PorscheMonster]

Awesome job! Thanks for sharing - love the amount of effort you all put into surface finishing the plug to achieve a really nice mold.

[@jakou31]

it's a pleasure to watch someone passionate by his job ... congrats !

[@4legdfishman]

Wow, very impressive. You are very talented. It's so smooth and perfect! Very inspiring to those of us who are looking to make our own molds. Thanks

[@johnnymckissick2735]

I would love to see a video of you running the infusion in the multi piece mold.

[@sofianebelghait6082]

Crazy Job i Love it, i m a Warships Modeler and i want a build a mold of model ships like this, Thank you very much to show us your experience and Ideas we learn from you.All the best and Good Luck. Sofiane

[@williamwightman8409]

You do beautiful work as a team. Congratulations on the finished product. I have a similar size one-time compound fairing (and mirror) to make. I chose to 3D-mill the foam from a CAD model, hard coat with epoxy, and fill and smooth. At that point I was going to use 50 microM thick polypropylene bagging sheet to isolate the wet carbon layup from the foam but I do not like the wrinkles left in the bagging material. I think I will use painters tape and release agent or lots of car wax. I will verify this part with a little experiment first. Then it is just a bunch of epoxy, peel-ply, carbon fiber cloth and some sanding and polishing. The final shell is a bit heavier than bagging and proper molds, but a very fast and simple process.

[@rogerimoveissc]

that what i call of high quality. impressive dude! congrats

[@carlandre3892]

This series is just amazing! Your skill and experience with composites is outstanding. I think your videos will be a great reference for a big project im gonna work on. I wish i could ask you a couple things regarding composites though. Great Work!

[@andreschavarria1450]

Thank you Carl! Just ask here in case you have any questions.

[@andreschavarria1450]

​@@JuniorProduction1000 no, it's a self designed horten nurflügel. See hortenmicrolight.wordpress.com

[@saiddope2241]

i'm outta words dude , very nice job u did

[@VinothKumar-qo7ry]

Tremendous effort. Thanks a lot for sharing knowledge. Huge respect for you sir.

[@JOEGGGJOE]

Snap, Crackle, Pop. Great video. Just think its,awesome that your wife helps you. Great job.

[@alkhan5445]

Looks like a labour of love. Makes me wonder if there’s a faster way. But then maybe these parts will last forever?

[@andreschavarria1450]

There's alwas faster methods. What's better depends on your requierements: cost vs. quality vs. effort vs. time. The molds show have a quality and endurance for a series production. If you have the respective $ and you need them fast for few pieces, CNC maching a block material might be your option. If you need only one piece, you want to keep it cheap, and are willing to invest some effort, making a throwaway positive core might be better.

[@davesolway3696]

not advanced to vacume and carbon yet but if my project works then things will change. Really enjoyed watching these. thanks for sharing it.D.

[@livewiretackle5698]

Great Work Andres! When are you going to post a post a video of you creating the final part? I am excited see your end product, This video series has been great. I learned a ton!

[@CSparzo]

Wow, that mold looks so good.

[@tko5106]

No video on vacuum infusing a shell from your multi-piece mold? If not, might you be able to point me to a video that demonstrates this process?

[@andreschavarria1450]

Sorry no video for this part. We used usual vacuum bagging this time: The piece produced is a pvc foam sandwich and infusion could have been used only for the outer face sheet. Here's more information on how we made the piece in that mold: hortenmicrolight.wordpress.com/2018/12/18/a-small-step-forward-every-day/ In principle it's possible to infuse the outer face sheet, wait till it hardened to bond the core add the inner face sheet using usual vacuum bagging. The molds need to be sealed with some acrylic sealant before srewing them together. This way you'll get a solid vacuum and will be able to properly infuse. We have a couple of videos showing the infusion process in general. The first one shows how the dry layup is made, and the second one shows the infusion process: kzbin.info/www/bejne/paeoioelotdmjJY kzbin.info/www/bejne/a4qyhWSKitykitU

[@accuratusindia5557]

Very professional mould making

[@MrMcbuck48]

You do nice work. Thanks for the info.

[@wofwof46]

CONGRATULATIONS ANDRE

[@vincentbarkley9121]

Wow! Incredible! Amazing!

[@u2ubemovie]

WoW, great job. What a craftsman! How did you make the 1/4 inch plywood guides? I must not have seen this post. Did you take each quarter inch plywood measurements from a drawing. If you have not explain this process, please explain. How thick do you suggest the foam should be? Please excuse all the grade school questions. However it is very interesting. Thank You!

[@joshuaerbe289]

This isn’t something homemade anymore, but factory quality. It is amazing! You must be German haha. Did you already finish this project/ if yes, do you have pictures of the end result?. I am thinking of making a velomobile. This looks like one too. Greets from the Netherlands

[@andreschavarria1450]

Thanks Joshua! It's a very long termed project (airplane). We made a nice piece in that mold, which is part of our cabin. There are several pictures of our project on FB, Insta and our quite detailed blog: hortenmicrolight.wordpress.com/2019/10/19/slow-but-steady/ instagram.com/hortenmicrolight/ facebook.com/hortenmicrolight/

[@nzkiwi9]

Question for the experienced composite wizards out there - Are you able to achieve a vacuum seal that allows you to seal and remove the vacuum pump, or is continuous vacuum pump operation required while the resin cures? If continuous pump operation is needed, would you find an automated pressure switch helpful in allowing the pump rest periodically?

[@andreschavarria1450]

Most of the times we could turn the pump off. For example, our vacuum is perfetcly solid when we make vacuum resin infusions. Sometimes we turn off the pump, but sometimes there is way to much material/effort behind the piece, so we do not want to take chances. We designed and built a simple pressure regulator for vacuum bagging. So in case the bag is slightly leaky, the pump goes on and off as needed.

[@CCROSS5882]

Now how about a part made from it? that was great.

[@stol1611]

Great job!! Thanks for sharing

[@calixtorodriguezleite9678]

Muy buen trabajo Chebarria, yo veo tus videos para fazer me un molde De un coche, espero tener suerte. Espero apreder mucho de ti. Saludos.

[@franciscoduarte1925]

Congrats very well done.👍

[@compspace]

why are you using PVA instead of a chemical release agent ? I think the surface would be better with a chemical release agent, or am I wrong ? Nice Work, I hope you continue to upload videos :)

[@dejayrezme8617]

Fantastic! But why did you use carbon for the mold? Was it needed? Is stiffness required for a mold? I would have guessed that a slightly more flexible mold might be better to release a new part.

[@andreschavarria1450]

Thanks! We used it for stiffness and weight. A stiff and light mold is better than heavy and flexible, which deforms on it's own weight. Also, I got the carbon for an extremely good price ;-) Releasing from flexible molds is indeed easier. However, much worse than fighting a little bit more to release is getting a premature release. That should be really avoided.

[@dejayrezme8617]

Ah thanks that makes sense. Where can I get this carbon for an extremely good price? ;)

[@andreschavarria1450]

It was remaining stock from GRM Systems. We had to buy the complete roll (over 120 m²), but we have enough material now for all molds we need.

[@frankmzemby9743]

I super like it

[@Quokkat7]

Thats really efing awesome

[@VENETIS-MAINTENANCE]

excelent work.

[@KarlHansenandcompany]

Very nice Andres ~~~

[@andreschavarria1450]

Thanks!

[@datinbin]

This is brilliant, can you tell what you were doing drawing a contour of the vacuum bag where there was local differential flow rate? Was it note it to do something with later or to change the port positions during production ?

[@andreschavarria1450]

Sometimes we draw contours to get an idea of the flow rate. Without markings it's hard to tell how fast it's moving. We usually aim at having a couple of cm or one inch per minute. The right speed depends on the laminate thickness: the thicker the laminate is, the slower the infusion front should be, so that the laminate is properly wetted.

[@lcctdesigner7158]

Thanks for sharing your fabrications. For me is a reference. Some questions: - Do you use HP-Textiles products? and in particular the Epoxy Gel-Coat (HP-E30FB aluminium-filled). - Do you have polished the Gel-Coat? (repaired?) Mucha suerte con la contruccion de su avion.! Carlos (desde Holanda)

[@lcctdesigner7158]

I see that you have give the answer (Formenharz P + EPH 161-P from R&G)

[@andreschavarria1450]

Hola Carlos, yes, we use HP-Textiles products. Mostly their resin infusion systems (HP-E120RI and HPE300RI). Though we bought a bucket of their gelcoat, we have not used it. Notice that repairing and polishing metall filled getcoats is in general not possible. This is because the metall particles produce a microscopically rough surface after sanding. We have polished Formenharz P + EPH161 from R&G, which works perfectly. This system is, however, not suitable for styrol based resins/paints. In that case, PVA release agent is a must to prevent direct contact to the gelcoat. If the pieces are large, I would strongly suggest to use a sprayable gel-coat. GRM Systems has one for a reasonable price.

[@lcctdesigner7158]

Hola Andrés, Thanks for your answer, you reply bring me in doubt. I thought that the HP-E30FB aluminum filled resin, was repairable and could be polished. I have read the HP description and the spec's sheet and I can't read anything about sanding or polishing, neither about repair procedure. It is a pity because I have all ready bought 2,75 kg bucket of HP-E30FB. I have read the spec's of the "Mould Resin P + Hardener EPH 161-P" and I think that this is what I need for my mould. The mould surface has been painted with water based car paint. I use and with good expericnces "Easy-Lease" realease agent (perfect stuff) from Easy-Composites in the UK. For this mould I have applyed 3x layers of Easy-Lease and 5x layers of "Honey Wax" (mould release wax) Regards, Carlos

[@eksekjut]

Hi Andres, thank you so much for sharing this. This gives a very good insight in mold making. Why do you put PVA release agent on top of the w-70 wax? You also apply small patches of soric xf in between the threaded inserts. What is the reason for that? Thank you for your answer. Love your work!

[@andreschavarria1450]

w-70 carnauba wax should be fine as a release agent. However, large curved parts are somewhat tricky to release. That's why we used also PVA, and still had to fight somewhat to get the part released. w-70 gives a great gloss and PVA reduces the needed force. The inserts should be properly embedded in the sandwich. Instead of Soric, you yould also use some thickened cotton resin or other strength bearing filler.

[@MrInnovativeEnergy]

I need to find one of those helpers.... I try to get my wife to help but she always say's I am doing it wrong or don't know what I am doing!

[@ultralinx200]

Duuuude!🤣 I think that 'helper' is his wife

[@carbonarne675]

Well done Warum habt ihr die Infektion von oben.gemacht und nicht von unten? Welches injektionsharz habt ihr genommen? Zur Zeit ist meine pumpe leider außer Kraft (kein drehstrom im haus) Kannst Du eine vollvakuumpumpe die mit 230v läuft empfehlen? LG and keep going!

[@andreschavarria1450]

Danke! Zu Deinen Fragen: Im infusionierten Bereich herrscht nahezu atmosphärischer Druck und die Fasern können sich wieder etwas aufstellen. Das kann man mit etwas Restunterdruck verhindern. Dazu muss der Topf ca. 1 Meter unterhalb des Bauteils sein. Das geht einfacher wenn man oben einleitet. Außerdem hilft die Schwerkraft beim Fließen. Leitet man unten ein, so muss das Harz im Laminat gegen die Schwerkraft fließen. Zum Harz: Wir haben das HP-E120RI von HP-Textiles genommen. Unsere Vakuumpumpe ist auch von HP-Textiles (HP-VZ1200). Wir sind damit sehr zufrieden.

[@alanswanson1952]

Wow very nice I want to do something similar to make a hull for a searey airplane. Why did you use carbon fiber for the mold? Isn't that expensive to do so?

[@andreschavarria1450]

We used carbon due to the lower weight and higher stiffness. Large molds can be quite heavy. For small mold this is irrelevant, but as larger the molds get, to more important it is to have a light but stiff mold. For this kind of job, you can get carbon fiber of B quality, which is still more expensive than cheap glass fibers, but much less than A grade carbon. Notice that most of the stiffness spending thickness comes from the Soric® core, so the needed amount of cloth is not that high.

[@sverker70]

Why did you use such a expensive material as CF to make a mold. Most use GF to make molds and CF for the item to be molded.

[@andreschavarria1450]

Though CF is more expensive, it has some advantages over GF for larger monocoque molds: weight is significantly reduced, stiffness is much higher, both ending in less deformation due to self-weight. Also, CF has less thermal expansion, which is better when heat treating parts in the mold. The mold we made before this one was a GF and Soric sandwich. It weights much more, needs a support and is much more difficult in handling than this one. Due to this reasons, I'll make all my future large molds with CF sandwiches. Sometimes you get cheaper CF, beause it has minor defects. The price is not comparable to CF used in part production ;-)

[@miniproto4721]

Super Video thanks

[@alisagtr]

good work

[@andreschavarria1450]

Thanks!

[@cesteres]

Awesome

[@abidfarooqui-sla3301]

Hi Andres: Just happen to run across this video by chance. Nice work. I just finished making a high heat mold (will get to 360 to 370 degrees F for every use) for a large canopy acrylic canopy that is to be vacuum formed. Used Axson Siko EL-315 epoxy resin and EL-215 surface coat. I did all wet layup (not infusion). I did make a mistake and the surface coat shrunk a bit in post cure and one can see the cloth print through. I was wondering if you have any ideas on fixing it. I mean I can just go to town wet sanding it smooth to a polish but just wondered if you have run into fixing surface finish

[@andreschavarria1450]

In this case I would carefully wet sand it til the surface roughness is fine. Any subsequent application of resin will make trouble sooner or later. Usually large canopies are vacuum formed with a lubricant and a thin fleece between plug/mold and acrylic. The surface has to be good, but not perfect. Polishing is maybe not needed at all. Epoxy resin without reinforcement tends to have more shrinkage. Plugs for vacuum forming ideally do not have a gelcoat. Only reinforcement and resin. In case a gelcoat is used, you should only appply a very thin coating. Just enough to create the surface. The same is true for usual molds.

[@abidfarooqui-sla3301]

@@andreschavarria1450 Great. That is what I decided to do also. Wet sanded it to 400 and then 600 grit. Got it fairly even. I am a bit lost on what you said: "Usually large canopies are vacuum formed with a lubricant and a thin fleece between plug/mold and acrylic". I am new to vacuum forming acrylic so if you can expand on this a bit for me, I would be very grateful. I built my own vacuum system and oven to heat the acrylic sheet and a hinged metal frame for the acrylic sheet that hinges and makes the sheet drop into the mould. Fleece in the US is type of fabric. Is that what you mean? What lubricant have you seen used in this application?

[@andreschavarria1450]

@@abidfarooqui-sla3301 I made a plug for a canopy of our airplane, but the canopy itself was made by Plexiweiss. Their process is confidential. I know, however, that they do not use vacuum, but pull by hand and they mendtioned the usage of a lubricant and some type of fabric/fleece between acrylic and plug. The process will depend on the type and size of canopy, though.

[@abidfarooqui-sla3301]

@@andreschavarria1450 Yeah I bet because once you figure out the process its not that difficult. So Plexiweiss is using a positive plug to do the canopy without even vacuum. That's interesting. I pull them using heat and vacuum in a female mould. It works but I may have to get mold surface better. This is why I was hoping you knew which cloth they used. I heat up the tool to around 300 F with the sheet on top clamped in a frame and then take it out and put the sheet in using a hinged frame sheet is on and then clamp it to the silicone seal on the edges on the tool and then reheat it to 350 F and pull vacuum. Since its not high volume production, I am good with it taking a couple of hours

[@Boscovius]

@@abidfarooqui-sla3301 I cannot speak for Plexiweiss, but I have seen a video of a team of men wearing welding gloves pulling a hot sheet of plexiglass down over top of a male canopy plug. The plug is covered in felt. It took 5 or six men to do this.

[@RodrigoNascimentoMattos]

did you infuse a part on this mold? how did you seal all the joints?

[@andreschavarria1450]

We didn't infuse, because we made a sandwich and had several pieces that were joined afterwards. However, we vacuum bagged and had to seal the joints. We used some acrylic between them before tighting the bolts. Acrylic from the hardware store is cheap and a great vacuum sealant.

[@alkhatieb]

very good content ,,, how can i learn this technique ? ,,, ich komme aus Ägypten

[@branislavbabic4579]

my not yet ready...

[@CristianGonzalez-qs3cq]

Hola Andres Chavarria, como puedo entrar en contacto con vos, me gusta la forma en q trabajas y me gustaria pregubtarte unas cosas. Un abrazo.

[@Стриж-КТМ]

Why use such complex technologies and expensive materials for the matrix? After all, the required rigidity can be gained due to the usual thick glass mat and simple resin.

[@andreschavarria1450]

There are a couple of reasons, including low weight and high stiffness. Large molds with full glass laminates are very heavy and deform under their own weight. The ideal mold is light but stiff. If you mean polyester resin by "simple resin", then you should consider that it has a much higher shrinkage than epoxy and is, thus, not that well suited to make molds of high precision.

[@RodrigoNascimentoMattos]

amazing. what king of gelcoat do you use? and the gelled resin s the same as the infusion resin? thanks for sharing!

[@andreschavarria1450]

Thanks! It's three different resins in total: The tooling gelcoat is Formenharz P + EPH 161-P from R&G, the infusion resin was HP-E120IR from HP-Textiles, and the gelled resin was the high strength laminating resin HP-E56L from HP-Textiles . All three are epoxi resins. I prefer the HP-E56L over the infusion resin for the coupling layer, because it has a lower shrinkage and is stronger. There are other tooling resins besides Formenharz P, which can be sprayed with a paint gun und end up in less effort. Ask, for example, GRM Systems.

[@RodrigoNascimentoMattos]

thanks for the fast answer. amazing. will look for them for my next molds!

[@CristianGonzalez-qs3cq]

Andrés Chavarría hola , me intereza entrar en contacto con vos. Como lo puedo hacer?

[@andreschavarria1450]

Hola, héchame un mensaje a través de hortenmicrolight.wordpress.com/

[@CristianGonzalez-qs3cq]

Andrés Chavarría gracias , fui pero no se q parte seria para mandar mensaje, osea no entiendo el idioma. Si podes ,mandame un email a mi correo, [e-mail] Gracias de nuevo.

[@RCjunkie]

I use clay or was to fill in the parting board

[@andreschavarria1450]

Body filler allows to make very sharp edges and isn't much more effort. Wax was only used to fill small gaps or gaps where sharp edeges aren't that important.

[@RCjunkie]

I have made mold for over 40 years no and has al ways worked great,wish I can send you some pics of it

[@mattlehnardt783]

sehr schon!!

[@michaelzajac5284]

What if it cracking?

[@andreschavarria1450]

In the first place, I would try to find out why it cracked. A well produced mold should not crack. If it cracked when separating parts or the pattern from the mold, then you should reconsider your release agent and its application procedure. The tooling gelcoat should be compatible to the used resin and you should keep the geltimes, so that bonding between gelcoat and laminate is good. Good tooling gelcoats are to some extend flexible, so that cracking should not happen unless air bubbles are between gelcoat and laminate. A cracked laminate is a clear sign that not sufficient material was used. In case it cracked while tempering, you probably had air bubles in the laminate or you didn't use symmetric layup. Repairing a mold is possible, but getting the surface right will be difficult to impossible. Sanding the spot and filling it with new tooling gelcoat could work. Use a gelcoat that can be sanded and polished. Sometimes it's better and easier to fill the damaged spot with some wax and polish the part instead of repairing the mold.

[@vespa2901]

Alles schön sauber verarbeitet, aber wozu das carbon in der Form?

[@andreschavarria1450]

Gewicht, Steifigkeit und geringe Temperaturausdehnung. Die Formen sind recht groß und aus Glas werden sie deutlich schwerer und elastischer. Die Form davor (kzbin.info/www/bejne/nGqlgIiOrZ2pqJY) haben wir in Glas gemacht. Diese hier sind im Handling viel angenehmer. Die Kohlefaser möchte ich nicht missen …

[@vespa2901]

@@andreschavarria1450 also nur eine komfortabilitaetsfrage? Weil auch carbon windet sich, wenn auch weniger. Die Steifigkeit könnte man ja auch durch rippen an der aussenseite realisieren. Ich frag nur, weil carbon doch schon bis zu 10mal teurer ist als glasfaser. Und am Ende ist es halt doch nur eine Form. Wie siehts sonst aus mit der Horton? Das Ding wird riesig oder?

[@andreschavarria1450]

@@vespa2901 Nicht ganz. Je größer und schwerer die Form ist, umso weniger Formstabil ist sie. Die Verwindung kriegt man durch quasi-isotrope Belege kontrolliert. Für den Formenbau würde ich keine Kohlegewebe mit Sichqualität verwenden. Es gibt ab und zu Restposten, die bei weitem nicht so teuer sind. Die Kostenunterschiede müssen ehrlich gerechnet werden: 400 g Kohle entspricht grob 1,2 kg Glasgewebe bzw. drei Lagen ...

[@vespa2901]

@@andreschavarria1450 OK das mit dem ehrlich rechnen hast du recht. Kohle wiegt bei gleichem Volumen nur die Hälfte von Glas stimmt das ungefähr? Um die verwindungssteifigkeit hinzubekommen könnte ich aber auch rippen auf der Gegenseite anordnen, oder spricht da was gegen? Also wenn ich hätte beispielsweise den Aufbau so gewählt, das ich nach dem gelcoat erst ne feine und dann grobe Glas schnitzelmatten anordnenen würde, damit sich der Kram nicht verzieht kaemen hierzu noch die rippen, ähnlich wie die Verbindungen deiner Form. Würde das deiner Meinung nach funktionieren oder gäbe es Probleme? Danke

[@andreschavarria1450]

@@vespa2901 Es ist nicht ganz die Hälfte (1,8 gegen 2,6 Gramm pro qcm). Entscheidend ist hier das E-Modul (Steifigkeit). Das von Kohle ist nahezu dreimal höher als das von Glas. Dann kommt noch das mit der Dichte hinzu, d.h. bei gleichem Flächengewicht baut man mehr Dicke auf. Streng genommen entsprechen 400 g Kohle somit 1,7 kg Glas. Mit den Rippen wäre ich vorsichtig. Wenn der Aufbau nicht richtig ausgeführt wird, können sich die Rippen bis zum Bauteil hin abdrücken. Die Lagen zwischen Rippe und Gelcoat müssen auf jedem Fall dick genug sein. Mehrere mm sind sicherlich notwendig. Geht es um eine Form für eine Vespa?

[@markrigby5130]

What brand of vacuum pump do you use? For large projects.....do you use multiple pumps?

[@andreschavarria1450]

We use this pump sold by HP-Textiles: shop.hp-textiles.com/shop/en/Vacuum-pump-220V-HP-VZ1200.html It's an Italian brand: D.V.P. model LC.4. It has enough volume throughput to evacuate larger parts. I would rather get a larger one for really big parts than combining several pumps.

[@kiyoshim9593]

I think we are missing one step here.

[@ВасилийНикулин-б7и]

Все норм и чисто!но стекловолокно не дружит с углетканью.есть даже какой то научный термин.

[@andreschavarria1450]

Углеродное волокно и стекловолокно можно хорошо сочетать, при условии, что стекловолокно не должно выдерживать никаких нагрузок. Например, слой ткани из стекловолокна часто помещают поверх ткани из углеродного волокна, чтобы защитить поддерживающий ламинат из углеродного волокна от внешних повреждений. Стекловолокно также увеличивает связь между углеродным волокном и другими материалами, потому что размер или отделка лучше, чем у углеродного волокна.

[@captainsledge7554]

What is it even for

[@andreschavarria1450]

It's for a cabin/fuselage of a microlight airplane.

[@ronaldbitter5783]

hast ne gute Frau!!!!

[@andreschavarria1450]

Jo, aus vielen Gründen ;-)