I checked the archives and did not see this one:
Has anyone ever tried using that spray can urea foam they sell at Home Despot as crack insulation to fill voids in rockets? At first glance it seems easier as there is no mixing, and it comes with the extension tube to allow injecting the compound into small areas.
Also, the harware store is closer than a West Marine or any decent hobby store.
Thanx
Al
I did. Not happy with the results. It sets up by contact with the air (moisture) and will continue to expand as time goes by. One fin can I filled expanded and deformed one side of the can. The two part foam PML sells is better suited.
John
The only problem with the stuff you get from Home Depot is that it requires air to cure. The top few inches will cure but everything under that will stay goowy. The 2 part stuff will cure all the way through.
Eric F
In addition to everything else mentioned the foam in the spray can, it tends clog up after the first use & you end up throwing the can away. I've used both & will never use the spray again. Mixing the 2 parts is less of a pain than we anticipate. -- Richard "beautiful weather & no nearby launches this weekend!!" Hickok
I had heard a negative testimonial about that. It seems that that formulation requires air to cure, and in the body tube it has insufficient air to do so fully. I would stick with the 2 part foam.
you can get it from Giant Leap at
from the GL website:
Expandable Foam - HIGH HEAT FORMULA!
...Locks fins into place!
We discovered this great product from a group of level-2 and -3 flyers in California. It?s a two-part urethane, closed-cell expandable foam that fills in the fin tab / motor tube area. Easy to use. After you epoxy your fins, just mix the two-part foam and pour into the fin cavity. It?s high-density structure helps hold the fins into place. The foam does not require oxygen to cure. Special heat-resistant formulation. Expands approximately 20 to 30 times it's size. Recently tested on an M-1939 certification flight. We were impressed.
Two parts 24 oz total...... $14.99
- iz
Al Gloer wrote:
this is an excellent supplier of all things fiberglas! Thanks for the link :o)
- iz
....Ed wrote:
I think it requires moisture to cure.
Mark Simpson NAR 71503 Level II God Bless our peacekeepers
There is a "non-expanding" version of the foam as well. A can because of compression has about .25 cubic feet of foam in it. It is a bit heavier than the expanding variety, but I have used it to good effect.
The expanding version will eventually cure all the way thru - say a year or two. I have some places we used it to fill cracks around a window cut in a cement basement wall. The worst spot was a 9 inch on a side void. We did that 8 years ago. We changed the windows this spring - and the foam had cured all the way thru.
I would still use the mix kind for a rocket, but if you are in a pinch the non-expanding is better than the expanding for a rocket.
Doug
Try:
Good stuff and good service.
David Bachelder
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