thinking of building a foamie...

[atahoekid]

You asked what the thinnest gauge aluminum that would work. I would worry about the sheets bending and flexing during handling and applicationand leaving creases I think it's discussed somewhere else on this forum and someone mentioned the thinnest guage but can't find it right now. Interested to hear how gorilla glue works. Mechanical fastening to roof spars would work but does that give you enough bond to make a good composite panel and the strength that it provides? I think I would glue the skin to foam and fasten if you feel the need but I think that is overkill.

[GPW]

Another source (s) from the Brit foamie RC guys ...

"B&Q should have expanded polystyrene sheets, (1" and 2" thick), they are usually in the building supplies section, (out the back in the larger stores).”

"If you need insulation board type foam check out a local branch of Sheffield insulation.My nearest one(Leeds)are very helpful,they'll cut an 8x4 in half if you ring them.”

QUOTE: “ So would you recommend tb2 on the foam, lay canvas on top, then a coat of diluted tb2 then primer then top coat? “ The underlined is entirely optional and IMHO , unnecessary ...

Lay the canvas over the TB2 , smooth it out to prevent wrinkles , allow to thoroughly dry , then prime and paint ... that’s It !!!

Ps. some canvas shrinks a bit in the long length ... must allow for that ...

[Trogdor]

Ah,

That's good about the canvas, I was wondering how to tension it and now I don't need too! Yes have had a wander around b and q they have plenty of expanded polystyrene, and polyisosomethingorother foam but no extruded. They used to sell it but not anymore these days!

Yes I was planning on buying my foam from Sheffield insulation but the foam is an odd size, 2500mm x 600mm, I have found knauf foam it seems possible to get it in 4 x 10 sheets which is perfect for the sides and will cover the roof nicely so I will see how much it costs. If its expensive I will buy the Sheffield foam and glue it together!

Atahoe kid, thanks for info, it makes sense that I don't want it too thin, something like .020 thick would be good? I plan on gluing it down and fixing it to the spars to make sure it won't delaminate as aluminium expands quite a bit and am not sure the glue will hold it in place.

Any thoughts on using a dimmer switch to lower current coming out of a transformer? Am planning to get it tomorrow so any opinions would be great!

[ghcoe]

I found a halogen power supply which puts out 5A at 12VDC which works well, the wire still gets a tad hot tho, but I was thinking of wiring in a dimmer switch before the transformer which would allow me to reduce the current? That should work?

The stainless wire will also help I think!

Cheers

I have read where people used a dimmer switch to control the current on a battery charger. Also, longer wire will cool the temp of the wire as mentioned above. I like the temp I keep my wire for safety reasons too. It cuts slower, but if I bump into it with a finger or other parts of myself, believe me you will, it wont cause a serious burn. A hot wire will cut through flesh as fast if not faster than foam.

[GPW]

... and if you’re grounded (standing barefoot in a puddle ) it may Shock you too ...

[atahoekid]

Ah,

Atahoe kid, thanks for info, it makes sense that I don't want it too thin, something like .020 thick would be good? I plan on gluing it down and fixing it to the spars to make sure it won't delaminate as aluminium expands quite a bit and am not sure the glue will hold it in place.

If I am right, and there's every chance that I'm not, I think someone recommended .032???? I'm relying on my memory which is VERY hazardous... I'll try again to find that thread

Does the foam provide enough thermal insulation to prevent the expansion and contraction?

[Trogdor]

Yes I wouldn't be using it barefoot, or when there is any water about! Have been shocked before and know its not nice!

.032" is about 0.8mm which sounds about right for the thickness of the aluminium, I will have to start saving as I bet its not cheap!

Will let you know how I get on with the dimmer switch tonight.

Cheers

[GPW]

Just a small consideration ... With the Al that thin it might dent easily and be difficult to repair later ... Unless there is a really good reason for using the Al skin , one might forgo that and use the more easily repairable canvas... Saving the expense too ...

[Trogdor]

Ah but it looks cool!

Thats the reason I am going with it as canvas would be better, I will be using canvas underneath to seal the foam in, I may end up going with a thicker sheet as its hard finding the thinner sheet in the length I would need. I think I will have to do some testing.

I am not too worried about the aluminium getting damaged, there aren't any bears or frozen turkeys here that could do much damage, just badgers? They wouldn't be able to reach so its cool.

[GPW]

Badgers .... EEK !!! Now that’s Scary !!! ... that and hedge hogs , and dormice .... Who knows what damage they can do ...

[Trogdor]

Well since I am yet to see any of them i think I am safe! Only badgers I have ever seen have been dead at the side of the road, and its will be harder to find them as they have started to cull them here.

I haven't seen a hedgehog in ages which is quite sad as you used to always see them. I have rescued a few in my time, they love dog food! Very noisey eaters!

Anyway I digress, I have got my gorilla glue in the post, and have bought a dimmer switch. Can't play with it tonight as its rained today and its wet out there!

Am having a very american day today as well acquiring american adhesives I went to an american cafe place in Liverpool for lunch which was very nice the key lime pie was especially nice! And to top it off we are going to a drive in movie tonight! Which will be so cool! Its called route 66.

OK another question, rreinforcing strips on top of or below the canvas?

Thanks guys!

[Trogdor]

Since I am going off topic with the voracious wild life we get here in the UK, I will bring it back on track.

I have been reading some more build threads, there are some many good ideas here!

Anyway I have decided to use fibreglass cloth instead of canvas as I have found some extra wide stuff that will cover my sides with no joins and its only a couple of squid more a metre.

http://www.ecfibreglasssupplies.co.uk/p ... -200g.aspx this is where I am getting it from I think 200g should be strong enough?

I am planning to glue this to the foam using TB2, and I will also apply reinforcing strips across the joins using TB2 and glassfibre tape.

For paint I think I will be going with Epoxy paint, in mikes thread someone linked to a UK supplier of water based epoxy paint which looks ideal!

http://www.antel-uk.co.uk/tds/waterbase ... ating.html

Does this all sound good?

I think Aluminium sheet would adhere OK to the epoxy surface? (For the roof?)

In the meantime I have been playing around with the hot wire cutter, the stainless wire makes it so much easier! Plus I have great control with the dimmer switch. The main problem I am having now is making wire in the correct shape, I have only been throwing the wire jigs together so this shouldn't be too much of an issue.

Any thoughts or opinions will be gratefully received!

Off to read atahoekid's build thread................

[atahoekid]

good luck with that. i didnt do a great job of documentation. I meant to but got caught up in the build.