Foam Types for Fiberglass Work

[@TheJonboix]

Excellent. I have done a lot of custom fiberglass over the years. Got several tips just now that would have been beneficial. Am considering reentering the fiberglass world. This video is a great start.

[@friedashabrang]

I really hope you keep this fiberglass series going. I'd be interested in seeing insert installation and more techniques for building hinges/ drawers and other projects.

[@TwistaFlip]

Great breakdown and information on the differences of foams. Was looking into building furniture that was lightweight, insulating, water/moldproof and strong for my boxtruck project and this video is very helpful

[@a.l.r.3006]

What resin you youse in stero foam. Nise video.

[@duanecrowley9820]

All going great but you didn't name the material at 16:20

[@MadelnOahu]

what were the names of the foams?

[@pcmountaindog]

So how well does epoxy/glass bond to these foams. I have bonded glass to the pink Owens Corning pink foam. It works but it doesn't take much to grab a corner and peal it right off.

[@chadrobinson3504]

Great question. "Badly". With closed-cell foams like XPS (Owens-Corning pink) it has nothing to grab onto. Coarse sandpaper can be your friend here although it'll never be as strong as other forms. With open-cell foams it grips very well, BUT you get a lot of extra epoxy in the pores as a result, which adds a lot of weight. The usual answer here is to apply a layer of "micro" (epoxy mixed with microballoons) first, then do the layup over that.

[@anthonygillesse7242]

Correct me but won’t the styrene in poly resins eat styrofoam. I believe only epoxy can be used with it. PVC foams are compatible with polyester resins, styrofoam is great for making projects that you want to remove the core with acetone

[@chrisybradshaw8594]

awesome ,i am making a waterbike and intend making foam shaped floats /tubes what is best foam to use ,,and is best to use epoxy or polyester resin, ,any advice on sealing please ,thank you for video

[@chadrobinson3504]

The resin type is a personal choice but they are not compatible so once you pick a system, stay with it. I prefer epoxy because there are many options available with different price points and features, and they are (mostly) all compatible with one another. (Also I have a lot left over from previous projects.) I would suggest blue styrofoam as is used for dock floats. It's closed-cell so it won't get waterlogged if there's a pinhole leak and is designed for buoyancy. It's often available cheap if you live near a lake and watch Craigslist or talk to your boat launch operators because it often gets thrown out/replaced as docks are maintained. It's also easy to cut with a hot wire.

[@chrisybradshaw8594]

@@chadrobinson3504 Thank you for the info, what foam do you recommend ,was thinking of XPS? then sheathing it with boat cloth and Epoxy, then painting with a flexible painted epoxy system that reflects the sun ,what do you think?

[@lakesidedjservices7615]

Hey Chad, thanks for the video! I'm trying to build a small teardrop camper with the foam core technique you discussed here!

[@lakesidedjservices7615]

I did my first test lay up with Foamular, and my resin just ate straight through the foam. :( It also ate through stryrofoam. Do you know what resins are foam-safe?

[@stuartmcnaughton2848]

Epoxy 100% solids no solvent epoxy.

[@Killemquietly]

Lakeside DJ Services I’m doing the same thing although I haven’t started yet. I did find out that if you put about five coats of latex paint on the foam first and then do the fiberglass it will not eat through it. You’re using the cheap stuff from the home improvement store aren’t you? Structural urethane foam will not get eaten but the cheap stuff from a department store well. However it’s way more cost-effective to just paint the hell out of it. The structural urethane is expensive like x 10.

[@mikelangieri6602]

Chad...Great video, good explanation of the foam densities. I want to build a custom one-off rear spoiler for my car and I was thinking that I might build skeleton type frame kind of like a spine across the trunk, which has a shallow curve side to side. Was thinking the triangular spine segments could be MDF, wood, or maybe one of your foam types? Once I had a multi-segment frame, I thought I'd "skin" it in a thin foam and then fiberglass it, almost like a surfboard. Which of the foam samples you show here would be good for curves and maybe even a compound curve? Thanks in advance for the advice.-Mike

[@kitkimbrough9441]

What do you use to prevent the fiberglass resin heat, and etc. From dissolving and destroying the foam, I'm not an expert but curious why it's not mentioned, since every piece you have in this video would be destroyed without some sort of barrier protection like latex paint, or etc.!!!

[@chadrobinson3504]

it takes a lot more heat than that to melt foam. So typically it's not a problem. You never want your epoxy "cooking off" (overheating) and once it's spread out it never builds up enough heat to be an issue. Latex paint would not protect from this anyway, and would drastically reduce the adhesion.

[@richyrich88]

Thanks , solid explanation. Straight and to the point.

[@simonadventum]

Which one should I use for building a boat? For the hull, stringers and transom?

[@michaelwarwick9930]

Hi Chad. Very interesting video...I'm venturing into GRP manufacture for a few drainage items that I just can't buy, so thank you very much for the brass tacks guide. :-) (Be careful with your descriptions, though. The white stuff you started with is what we in the UK call 'expanded polystyrene' (EPS) ...which is not 'Styrofoam'. Styrofoam, besides being a trade name rather then a generic plastics identifier, is extruded polystyrene (XPS). XPS is nominally waterproof, whereas EPS definitely isn't - which is why nobody makes cups or takeaway trays out of it. As for the lightweight blue and ochre stuff you were working with, this looks very much like PIR (polyisocyanurate) or PUR (rigid polyurethane) foam - which over here is used as insulation board. Both are very easy to work with - but incredibly dusty and potentially carcinogenic. PPE is therefore a must, so your viewers need to be very aware as to what they're using.) Best regards, Mick PS I'm a structural engineer, not a chemist, so please don't take my word for the above.

[@torstenhansen4308]

Hi Michael, I for one appreciate your comments about the various foams shown here and thought you might value an American response. I have worked with foam extensively for insulation so that’s my perspective. As you point out, EPS is not as water resistant as XPS but it is manufactured to different densities and is in fact used extensively for liquid and food containers here in the US. The blue foam Chad is working with is XPS, probably manufactured by DOW Chemicals since blue is their color. The same material is also widely available in pink manufactured by Owens-Corning, the Pink Panther. XPS should be fine for form work but I would not use it as the core material in a structural part due to its low shear strength. For that, the PVC foam is much better according to my limited research. You are spot on about the polyiso board, it is nasty itchy stuff when cut and PPE is a must.

[@MattJerikoG]

Hello! I’m trying to creat a custom bodykit for my car with fiberglass but first I need a mold. What is the best foam you recommend for this type of project and where can I get it? Also how can I stick the foams together to make a big piece for a bumper?

[@hojjatahangarikiasari7670]

Hi, is Polyurethane Foam Board good for building a truck camper?

[@chadrobinson3504]

I would probably be using that for at least a part of it, especially compound curves. You'll probably find that some type of rigid styrofoam is better for large structural pieces like the sides and roof. You can absolutely combine foam types, using contact adhesive, epoxy, or any other similar glue between different types. Just be careful to remember that most urethanes should not be cut with heat. With styrofoam it's common to use hot wires to cut a long templates to make shapes. But you would never want to do that with a urethane, because most release toxic gases when cut that way. Urethane's need to be sanded, cut with a knife, or other means to shape them.

[@DrShout]

A few years ago, I worked with a man that made cabinets for his work trailer using a green or blue sheet of foam. It was probably 2”x24”x8’ and in order to make thicker projects, he would use tent stakes pushed through 2 or 3 sheets. This foam was light and hand contourable … he would curve the corners with his hand and stiffen areas by making a channel with his fingers, then would apply a indoor primer, let dry than add a green releasing agent. Fiberglass the whole thing with several layers of fiberglass. Using a Zip Tool he would cut the doors out, then reach in and remove the foam in pieces by hand. Do you know the name of this type of foam?

[@chadrobinson3504]

Most polyurethane foams are sandable. When we built aircraft parts we would typically use Last-A-Foam although that's not the only option. One thing to watch out for, the more sandable/shapeable a foam is, the weaker the fiberglass adherence to it. You typically need to make a thick "micro" slurry to apply to the foam before glassing it to get any kind of bond, and even that is weak. Don't use this for structural components that need to carry any bending or torsion forces because the glass can delaminate and the strength is lost.

[@chadrobinson3504]

I just re-read your post. The color is a giveaway. Last-A-Foam is yellow so it's probably not that. It was almost certainly Divinycell (PVC). That's usually blue or green when sold.

[@DrShout]

@@chadrobinson3504 What I need is a foam to break away from the fiberglass. The foam is not part of the final structure. As if you’re making a fiberglass box to put something in once fully encapsulated by the fiberglass, I use a ZipSaw to cut an access into the unit and the foam is removed. This foam breaks easy, yet very very contour-able without the use of any tools/knifes/hot wires.

[@chadrobinson3504]

@@DrShout I'm actually going to be doing that very thing in a video in the next week so stay tuned. Meanwhile you have a few options. An easy option in many cases is to cover the foam plug with duct tape. The fiberglass will pull right off once it's cured.

[@DrShout]

@@chadrobinson3504 This foam was so workable, for the indentation above the tent stake, he would take some scrap piece, get his pocketknife and cut a shallow plug size circle in the scalp piece and then just push and twist it on top of the tent staked area… it would hold and then just rub his hand across it to smooth it flat. Almost visually seamless.

[@gbs7144]

Can you use epoxy resin directly on every foam you've shown here?

[@hobogreen3750]

yes only epoxy resin, not polyester it will melt them

[@carlericvonkleistiii2188]

Are you aware of whether these foams are stealth compatible? Are they detectable by radars?

[@chadrobinson3504]

LOL that's a first. I'm not sure what you're up to, but both foam and fiberglass are transparent to RF - it's common in Cozy MKIV and other aircraft to "bury" antennae under the "skin" for streamlining purposes. I would think that applies to radar as well but a pile of foam is going nowhere without an engine, and that's going to be like a spotlight. I'd be more concerned about metal components in the long run.

[@carlericvonkleistiii2188]

@chadrobinson3504 Just curious. Wondering how the Ukrainians do their drones to defeat air defenses.

[@chadrobinson3504]

@@carlericvonkleistiii2188 It's a fair question. I don't know for sure, but drone hardware is such a commodity these days that I imagine it's easier for them to buy and customize off the shelf items. Fiberglass composites would probably be good choices if you wanted to make one but again I think the secret sauce would be in how you hide the engine, payload, avionics, and other components. Those seem much harder to me. When it comes to things like RF and radar the most useful thing IMO is that transparency to RF means you can do streamlining very effectively. Most aircraft are covered with antennae and sensors because aluminum bodies require that. With fiberglass (NOT carbon fiber, though) you can put them "inside".

[@carlericvonkleistiii2188]

@@chadrobinson3504 I realize the signature of metals would be high, but thought some rubberized paint incorporating metal flakes (not powder) magnetically aligned during the rubber (or resin) curing process might absorb/misdirect the metal around the engine and control areas. Then use fiberglass pushrods for the control rods. Have y'all any experience with wire guided drones?

[@chadrobinson3504]

@@carlericvonkleistiii2188 I would say I have some book knowledge more than field experience. Those concepts have a lot of carry-over in other domains and I did some research here for a startup doing drone-based monitoring of construction sites, but I would never pass myself off as an expert.

[@Mat-Jak]

Which one would be good for a custom car diffuser?

[@chadrobinson3504]

That depends where it's going. These foams don't have very high heat tolerances. For something like an intake air scoop any of them would be fine, so I imagine you'd want something easily shapeable like one of the polyurethanes. For something that needs more heat tolerance you might want to use any foam that shapes well as the base, do a layup over it, but then take out the foam. This is a common technique for thinner parts, too - you cover the foam with duct tape or similar as a "release."

[@Amdraz]

Chad Robinson nice video, I'm just about to start building a plane and this is really useful!

[@ab6565]

Very informative, thank you for sharing! I subscribed but I'm not seeing any more projects; what happened?!

[@chantelrhine8965]

It depends on the resin your using because polyester will melt that styrofoam

[@adrian17cy]

Excellent video!

[@flrican3938]

What about EXPANDING FOAM?

[@stevebroddc]

Good video. Would be helpful if you stated the names of the products more frequently

[@doesntmatter3068]

This is why i came here, THE NAMES! ....this foam, or that foam........maybe its called Your foam?

[@74hdo]

Thanks for the video. But guys you need to be careful about expanded styrofoam, it is not waterproof, I think it is better use extruded styrofoam in the presence of water.

[@fswiegelaar]

Hi Chad, nice info, thanks.. I am building a tank with an odd shape and shaped it from Styrofoam (the white bally one). I am having an issue with getting something to seal it with, as I want to make a fibreglass mold, but the resin is chewing it.. Any suggestion to what I can use to seal off the styro?

[@TheLightDivides]

You can use titebond wood glue over the styrofoam surface and than glass using poly resin.

[@1951Roy]

Question Chad, I am rebuilding an RV. Could i us the PVC and fiberglass to build a floor. I am looking for something lite and water proof. Good video/

[@chadrobinson3504]

+Roy Vannoy Absolutely! The Cozy regularly embedded aluminum in fiberglass layups for things like landing gear hardpoints. There's no reason you can't do the opposite. To get a good attachment between the aluminum and fiberglass you need to rough-sand the aluminum first, and it's best to drill some holes in it as well. Check out the CozyGirrls' Aileron Hinge Mount to get the idea: www.cozygirrrl.com/cg_products_cozy_mkiv.htm

[@viewsandreviews180]

You may have covered this in other videos but can a sheet of foam be heated and bent? I'm not looking for a tight radius just something like a two to three inch (50 to 75 millimeter) radius out of a 10 to 12 millimeter sheet.

[@chadrobinson3504]

Sorry I missed this question... I've never worked with a foam that could be reliably bent - they're all very "brittle" and crumble/sand/break easily. However, they can all be easily shaped. When you want curves, typically you don't bend them - you shape them. In aircraft construction it's very common to use weaker "5-minute" epoxy mixes (the two part quick-cure ones you can get at the hardware store) to stick multiple pieces together, then sand and shape to get whatever final curve you want. Then you lay up over this. Remember, the foam is providing rigidity and crush-protection. The FIBERGLASS is the structure. So any glue will do - it doesn't have to be strong, just stronger than the foam. 5-minute epoxy is perfect. When making Cozy wings, pieces are common stuck together with spray-on adhesive!

[@jdog4534]

What's a layup? I thought that was the number one move in the WNBA. no?

[@htpservices1863]

Can you use these foams for carbon fiber as well?

[@bigglesbuilding3348]

yes

[@NoI.D.]

Hello Chad. I am planning on doing some modifications to my car using the styrofoam and fiberglass method. I have zero experience with this as it will be my first time. I am looking to use my vehicle for the Children's Hospitals. Could you shed some light on this for me? Great educational vids my man!

[@joeking5223]

More lighting please

[@efrainberrios8494]

Great video and well explained too!, thanks for posting!, I subscribe to your channel too.

[@dwaynemcallister7231]

Aircraft Styrofoam is large cell, hardware store styrofoam, is usually small cell. For laying up glass, large cell allows epoxy to bite into the foam, stronger and less chance of delamination. So they tell me

[@maggie4834]

What’s the best source for reasonably priced pvc foam?

[@blanchae]

Very well done video. Thanks for posting.

[@blanchae]

blanchae I understand that there are differences in the fiberglass resin used based on the foam type. Some resins will melt the foam if not matched. What's your experience?

[@brandendebuhr2997]

Where is a good place to buy the structural foam?

[@chadrobinson3504]

Great question! All of these foams were used for a Cozy MKIV project and I definitely recommend the two main suppliers in that category: www.aircraftspruce.com/ and www.wicksaircraft.com/. You can occasionally find other types in a bunch of other spots. For example, high-density styrofoam you can scrounge from old dock floats, often for free. Urethane "pour" foams can be bought at the hardware store (although their quality is low). Etc.

[@clydecox2108]

Very interesting

[@davidlindquist3113]

Poor video quality. The backlight from the open garage door ruins the video.

[@awstutorialseries]

+1 for cloudability shirt

[@AirBikeUK]

B

[@StudioSomethingChannel]

you are so obsessive bro you obviously need to be packing up your belongings so you can move to the new house, the mother of your 4 kids is probably pissed you are making a video for youtube rn........good fiberglass tips tho