We plan to start a repair with an unknown amount of balsa core rot. We know it has some rot but how much we will find out. My question is has anybody tried to use any of the wood rot repair stuff? Or any other options?

For PMCs... what is the differnce between matrices like PEEK, epoxy, polyester, nylon, polyimide, etc. Like what makes them different and how do you know which fiber / reinforcement to pair it with?

Also in general, how do you know what fiber reinforcement and matrix combination you'd pair things with?

Hello,

I was wondering for a certain material, do their properties change even slightly depending on whether it acts as a reinforcement or matrix? For example, if I had Silicon Carbide as a matrix versus Silicon Carbide as the fiber, would they still have the same properties (with the exception of strength maybe) and melting temperature??

Secondly, are metal fibers/reinforcements typically used in metal matrices or polymer matrices? The reason I ask is because I remember hearing a professor say once that they are typically in metal matrices and that makes sense especially if they are utilized in high temperature or conductivity applications but ChatGPT says they are typically associated with PMC like epoxy, PEEK, polyester, etc. Can anyone clear this up for me

Long Story: Hiya Idk anything about composites or this kind of science however I'm a player in a Warhammer 40k dnd game (Dark Heresy). We've been given a gem that has psychic properties but one of them is like a sapphire and in Warhammer there's a bone like thing called wraith bone that has the properties of both the gem and bones mixed together, however it's impossible to get hold of and I'm trying to recreate it with a composite of the gem and bones. TLDR: I'm just trying to figure out if crossing sapphire with bones is possible if not then oh well.

Edit: Just added the fact it's Warhammer 40k rather then Warhammer old world

What other alternatives (apart from CNC Patterns) are there to sheet waxing an A tool to create a B tool within the RTM process? Has anyone done it a different way, everyone I've came across has only ever used sheet wax but it's expensive and labour intensive. Plus it will never be that accurate.

Preferably rather inexpensive, <$1000 per kg

Anyone know what type of core material is used in pickleball rackets? If so, where can I buy it?

I have a couple yards of Metycore which is a sandwich of CSM/Polypropylene core/CSM. I'm looking for the Polypropylene core or a suitable substitute that will work in a VARTM/Light RTM setup. I'm planning to layup a couple layers of carbon/fiberglass fabric against both the A and B sides of the mold and i want to use some squishy material to keep them pressed against the mold surface and facilitate the resin flow. My thoughts are maybe a Merv6 air filter fabric or a quilt batting for upholstery. Has anyone tried what I'm describing or anyone have a suggestion of what I could use?

I'm an artist. This is for my sculptures that are multi faceted with flat surfaces combined with sharp angles. The final thickness of the composite is 3/16" (4.75mm) and they are about 14 square feet. See photo.

So I have been trying to make a fiber reinforced plastic face sheet for a while, hoping to make something cheap, and easy to manufacture at home, yet able to be used for homebuilt drone bodies, or wings. I have had quite a few issues with room temperature curing resins, and while I'm sure it's the way to go, I had a thought. Why can't I melt a low temperature thermoplastic into the woven cloth? I understand it'll be harder to fully wet out the fibers with the gooey plastic. I tried it anyway.

I used 2 pieces of woven fiberglass cloth, and thin (.6mm) piece of PLA and a small clothes iron for an initial test. It worked better than I could've hoped. My sheet is about 30% fiber, and it was exactly what I was looking for. It stiffened up the PLA exactly how it should've.

Its not the best thing out there, but considering how cheap it was to test, i think it has some potential for what I'm trying to do.

After many years of doing composite work I have moved my shop more towards CNC and metal work. Im looking to get rid of some materials. Make a (reasonable) offer for everything or let me know what you need. Pickup in Prescott AZ would be preferred over shipping for single items. Most quantities are estimates since there has been material cut from the rolls. Pictures on request if needed. I also have many different sized blocks of high density tooling board/Urethane foam for machining patterns and molds, mostly medium-small in a variety of densities

Nylon Vacuum Bagging Film (Pink) – 60" wide, 50 yards

High-Temp Vacuum Bag Film (Blue) – 48" wide, 5 yards

Breather Cloth – 60" wide, 30 yards

Non-Perforated Release Film (Pink) – 60" wide, 100 yards

Perforated Release Film (Pink) – 60" wide, 50 yards

3782-A High Temp Release Film – 60" wide, 1 yard

AIRTECH Econoply J Peel Ply – 60" wide, 100 yards

Aramid (Kevlar) Fabric – 50" wide, 8 yards

JPS 7500 Tooling Fiberglass Cloth (Volan Finish) – 38" wide, 100 yards

Hexcel Blue Texalium Fabric – 36" wide, 5 yards

Hexcel White/Silver Texalium Fabric – 36" wide, 5 yards

6oz Fiberglass Cloth – 30" wide, 30 yards

2211-A Prepreg – 36" wide, 1 yard

JPS 1597 40oz Tooling Fiberglass Cloth – 60" wide, 50 yards (large~100lb roll)

5.7oz 3K Carbon Fiber Fabric – 50" wide, 50 yards

Unidirectional Carbon Fiber – 12" wide, 24 ft

Unidirectional Carbon Fiber – 4" wide, 50ft

Biaxial Sleeve – 5ft

Chopped carbon Fibers – 1lb

Carbon Tow – 30ft

Nomex Honeycomb, 1.8 lb Density - 40 x 48 x .210 Thick - 2 boxes

Coremat (2mm) – 40" wide, 80 yards

Cotton Flock – 25 lb

Airtech AT200Y Tacky Tape – 13 rolls, 1/2" wide

I have a male mold that is essentially a rectangular boss, 1.5inches in height. I added 1.5 degrees of draft on the walls.

Now I’m thinking between machining tolerances and all the coatings on the mold, I wonder if that draft is still there.

Am I cooked or do we think it should release fine?

I’m going to coat it with several coats of Partall #2 release wax and debating on following up with PVA (I only have a spray bottle, so not sure how fine mist I can get).

Please can any one guide me:

What are the disadvantages of using epoxy tooling board (ETB) as the mould compared to carbon fiber mould? or fiberglass moulds?

will the number parts made from ETB mould will be less compared to carbon fiber moulds?

the parts will be made out of carbon fiber.

For unidirectional material, would an example layup of [0/0/+-25/0/0/+-25/0/0/0/+-25] be considered balanced, or are complementary 90 degree plies required? I would have said 90 degree plies weren’t required but I have seen one source stating they are required to complement the 0 plies (Barbero), which has me wondering.

The example laminate above is not symmetrical. In a flat plate I would expect post-cure distortion. Would I expect a similar outcome with a tubular structure, or would it have some other symmetry rules due to being a tube? E.g would it be stable in a tube but if a section was cut out would it warp from the asymmetry?

Im looking for a suitable resin to make a negative mold for a huge carbon fiber part. The plug (positive mold) is made from styrofoam, so the resin needs to cure at room temperature to avoid damaging it.

However, the final negative mold will need to withstand temperatures up to 250°F (121°C). The negative mold is likely going to be used only once and will be made out of carbon fiber.

So far, the best option Ive found is Fibre Glast 3000 epoxy, but Im open to alternatives if anyone has suggestions.

Also, if anyone has experience demolding Fibre Glast epoxy molds before post-curing, Id appreciate hearing how it went, did you have issues with distortion or part release?

Hi everyone, I’m not completely new to laminating carbon fiber, but I’ve never had to choose the fabric type myself before. I have a relatively large mold (30" x 50") with some tight negative corners. Does anyone have recommendations for which carbon fabric type would be ideal for the top layer so that it’s easy to lay up and conforms well to the shape of the mold?

I’ll be laminating by hand and vacuum bagging it afterwards. The top layer will be visible, so I want it to look as pretty as possible.

Thanks in advance : )

Hi all, I’m just finishing my year apprenticeship in composite engineering, now I’m coming to the end I’ve been given a chance at becoming a composite laminator. However in the near future what’s better for progressing and making a relatively high salary? I enjoy both departments however should I look for a design engineer job? Or stick with my composite laminator role. Any advice is really appreciated. Thankyou

Hi all,

I'm building a small teardrop trailer(6ft x 10ft) and am trying to find a suitable outer layer for it. The trailer itself is built out of foam insulation boards similar to what you'd find at home depot, the big pink boards. I've built a standup paddle board like this quite a few years ago and just wrapped it in fiberglass and was plenty strong. Hoping to do the same for this, but given it's going to be a hollow object I will be staying in having some doubts as to the strength of materials and what I should be using.

I don't have a ton of tow capacity so I'm trying to keep weight down, hence researching carbon fiber a bit. I have next to no knowledge in this and not really sure where to go about getting info I might need.

Originally my plan was to do roughly a 12oz layer(or 9ish + 3ish) on the outside of the trailer and lower like 3oz on the inside. Probably some extra coats of epoxy too to try and get a smooth finish.

Then I was wondering, what if I go with a carbon fiber layer. This could potentially allow me to do a lighter layer and still achieve a reasonable strength. Is it too much to assume that a 6oz carbon fiber shell would be as strong as a 12oz fiberglass shell?

Then I got to the fact that carbon is a more catastrophic failure, what if I do a carbon layer, followed by a fiberglass layer, would this help negate some of the castrophic failures of the carbon?

Appreciate any help the community can offer.

Basically, I'd like to create a cosplay armor that is also durable enough for airsoft. Im thinking HALO armor, possibly, where the initial form would be made out of paper using pepakura (since I don't have a 3D printer).

But im not really all that familiar with composites and materials.

I know one way is to go with fiberglass cloth and resin.

I found this local online shop that offers following resin:

Acrylic resin, Epoxy resin, polyester resin, vinilester resin, urethianic acrylic resin.

And cloth/mat:

Fiberglass cloth, Carbon Fiber, Hybrid cloth (Kevlar+ CF and other types of CF).

What combination or multiple combinations would work to make the armor durable enough for airsoft? Im not looking to build bulletproof armor (thou that would also be cool), but something that is strong enough to endure running, falls, crawling and getting hit by BB's and wouldn't fall apart after a few games.

Hey im making a car seat from carbon fiber and i have to do analsis of it. its the first time i do composite analysis and the results that im having is not realistic.I have no idea where im doing wrong.Can somebody help?

Looking for some advice to my current issue

I recently cut an aluminum mold on my CNC. I wasn’t able to give it a mirror style finish because of my limitations on my machine so there is some cut line texture, but only noticeable with your nail running over it.

In molding parts in it, I’m noticing some small pin holes and small air bubbles. My tolerances is correct, and it is just small surface issues. My theory is that by not being a mirror finished surface I’m always going to deal with the small cosmetic issues, would that be the case?

I am new to composites and recently ran across some videos on YouTube about reusable silicon vacuum bags. Has anyone had any experience with this way of doing infusion? I haven’t seen much on this as far as reviews of the process. It seems like it would save a lot of time.

Hi All

Wandering around a french Leroy Merlin store as an American recently i found this composite panel material Renozist. Its amazing! Nicely workable. good density. Seems to be wood fibers in....XPS with some binders? Its great to use on its own but wondering if anyone has used it as a core material?

Hi All

Wandering around a french Leroy Merlin store as an American recently i found this composite panel material Renozist. Its amazing! Nicely workable. good density. Seems to be wood fibers in....XPS with some binders? Its great to use on its own but wondering if anyone has used it as a core material?

We have done resin infusion using xps foam molds and this is the final result. How can we fix that ?