LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently Sun Apr 20, 2014 11:06 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 4 posts ] 
Author Message
PostPosted: Sun Oct 23, 2011 1:01 am 
Offline

Joined: Fri Jul 15, 2011 8:34 am
Posts: 29
Location: Germany
Is it possible, or did somebody already have a try "blowing" composite material out of its mold from various directions ?
Fiberglass & co do often get blown out of the mold, especially after resin infusion. I had the simple idea of integrating many hose connectors into the mold, leveling them with clay and pressurizing them after the layup has cured in order to release complex part safely from the mold.

(I really have no Idea why I felt like asking about this Idea, especially because there is no composite work to be done soon)

_________________
Image


Top
 Profile  
 
PostPosted: Sun Oct 23, 2011 7:26 am 
Offline
User avatar

Joined: Fri Jan 02, 2009 1:45 pm
Posts: 873
Location: Halifax, Nova Scotia
Air will not replace a release agent.

My summer job after my first year of engineering studies (40 years ago?) was working for a boatbuilder, where 50 percent of my work was laminating GRP sailboats. The mould had an air fitting down by the keel, just as you describe. When the layup had cured overnight, we'd apply some air and "pop goes the weasel", after which we just lifted the (16 foot) hull out of the mould.

But ... this presumed that we had done a good job on waxing the mould (we used paste wax rather than commercial release agent because it gave a better surface finish). If on occasions the waxing was deficient, or a mould was developing hairline cracks from age, then boat and mould were wonderfully fused together, requiring application of saws and chisels to remove the boat in bits. After a second such incident, it was generally taken as evidence that the particular mould was destined for a fire in the back yard (this was in the bad old days when we did burn such things - it made quite an impressive and dirty fire).

_________________
Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601


Top
 Profile  
 
PostPosted: Sun Oct 23, 2011 3:30 pm 
Offline

Joined: Mon Jan 22, 2007 5:13 pm
Posts: 309
Location: Anchorage Alaska
Yes, one or more air fittings will help pop a part loose but multiple coats of a release agent is critical in every job.
Air just makes it a bit easier but is not necessary.

_________________
Attitude =
the Difference between
Ordeal and Adventure
James


Top
 Profile  
 
PostPosted: Mon Oct 24, 2011 1:14 pm 
Offline

Joined: Fri Jul 15, 2011 8:34 am
Posts: 29
Location: Germany
exactly what I thought about, thanks (did not know such things are already done)
I would not even dream about laying up something without some release agent ;) but very often it happens that you're facing a cured product stuck in the mold and things feel like it could break if you apply to much force... next time I will try this

_________________
Image


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
POWERED_BY