Fiberglass

The Rocketry Forum

Help Support The Rocketry Forum:

UPscaler

New Member
Joined
Nov 25, 2009
Messages
4,278
Reaction score
221
I saw aa video of a guy using polyurethane instead of epoxy resin, is this a good idea?

Thanks
BC
 

troj

Wielder Of the Skillet Of Harsh Discipline, Potent
Joined
Jan 19, 2009
Messages
14,339
Reaction score
245
Polyester resin will work, but the challenge is that it doesn't bond to epoxy, and vice-versa. This matters when things like fillets and other such bonds are done with epoxy.

In addition, polyester resin is a much nastier product, and requires proper respiration, etc. It shouldn't be used in a home, or attached garage.

-Kevin
 

dave carver

....what hump?
Joined
Jan 18, 2009
Messages
4,973
Reaction score
5
Location
Idaho
The catylist for polyester resin is a deadly chemical, 1 drop in your eye and it's gone type of stuff. 200 mg on your skin and you will not like what happens to you.

This is why major wooden boat builders use epoxy/wood for showboats running into the millions of dollars.

All in one word:

Safety
 

kramer714

Well-Known Member
Joined
Jan 20, 2009
Messages
715
Reaction score
24
MEKP (catalyst for Polyesters and Vinylesters) is hazardous, but with care can be used safely. It is routinely used commercially and is, the curing agent for Bondo.

No matter what you use, be smart and be safe.

I have helped a number of people with composites for rockets (I work with composites as the 'day job'), I suggest that they use epoxy resins for a number of reasons including;

More forgiving of use temperature
tougher - better mechanical properties
surface cure without additives
less shrinkage during cure
lower odor

Polyesters have advantages too,
lower cost
adjustable gel times (can get them so they don't run)
quick cure times
can use gel coats
works well with mat glass

I think the advantages of the epoxy offset the advantages of the polyester for making parts, polyesters may be better for mold making.

what ever you use, be smart, safety goggles (not glasses) are a must, have good ventilation, keep the area clean, have a fire extinguiser handy, wear a protective hand cream AND gloves (use two pair of gloves, that way if you need a clean hand, pull of one glove and you still have one on). After handling chemicals wash well with COLD water.

just my opinion....
 

Latest posts

Top