Looking for an ultralight, large fill material

Hello

While not specifically going to be used for boating, I'm looking for an ultralight fill material for filling voids in a carbon fiber part.

I debated a two part urethane foam, but would like something a bit harder.

Right now I've played with the West Systems 410 micro light, and some Q Cells.

Both are pretty good, I cannot confirm, but I believe I had a bit of expansion/contraction with the 410. In hot weather I had some hardware binding, so its off the list for me. just wondering if there is something even lighter out there.

Thanks in advance

 

Is it only cosmetic, does it need to be painted?

 

I'll give better info.

The fill is for a composite rifle stock. I'm looking for a light fill for the non-structural pieces, the butt and the forearm. The action, where much of the force is concentrated I use a fiber reinforced, fill, epoxy based fill.

So the material does not need to be painted. It is just cosmetic, just filling some space, but giving some compression assistance And if I did, I figure I can skim coat with something prior.

It will need to be machined and sanded.

I'm staying away from the foams mainly for cost. In AK, all these foams fall under hazmat. So its just spendy to get them up here. I can get the smooth-on foams up here, but in the larger kits. I just don't need that much material, and don't think I'd use a kit before shelf life expired.

That's why I'm looking at an additive I can use with epoxy. I can get epoxy no problem, then only mix what I need.

I do like the q cell stuff. I've been mixing to a "just pourable" consistency. Maybe I'm not fully taking advantage of it?

Thanks

 

How thick is the coat you need?

 

I'm using it in depths of 2 inches. With the q cells I have to do small pours or I really heat up.

 

How much time for the job? A honey comb made in pieces, a grid, some bulkheads. Materials as corrugated cartboard, matches Etc..

 

Maybe some of this stuff added to your epoxy fill?

http://www.walmart.com/ip/Bean-Bag-Refill-1.75-cubic-feet/14321236
http://www.amazon.com/Single-Stuffing-Shipping-Packaged-Shipped/dp/B00EOUM3D4

 

Maybe letting it heat until it foams just right will give you an alternative to PU foam.

Dino

 

Like the foam ball idea. I'll try some out. That looks like the ticket!

 

Hey youngtrout, if you post cure the q cell mix say too about 180% you will get less movement. Also try a bit thicker mix, you'll just have to pour it slowly. The more q cell you use the lighter the mix. Maybe great stuff foam? If you could control it some how, again a little at a time let it expand than a little more. It's pretty rugged stuff I filled a hollow keel with it a while ago and would do it again....................g

 

Also use a slower setting epoxy and try to keep temps down. Q cells are full of air so they will expand with heat with a fast cure, then as it cools the Q cells will shrink again. So stabilising the temps when curing will help a lot in terms of immediate shrinkage after the initial cure.

 

Phenol spheres are going to be the lightest, Q-cells a bit heavier and 'glass balloons heaviest of the three.

 

Would you consider Perlite?

http://en.wikipedia.org/wiki/Perlite

 

Perlite is light for the minerals, but not really so much so compared to spheres and balloons.

 

Thanks for the responses. I kept adding the q-cell till I was getting almost a clay. It really did work well. Bit of heat but nothing extreme. Going to pick up some Phenol spheres. While my mix is very solid, if I could shave a few bit it would be good to.

Thanks for the responses,