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The Artful Bodger
03-30-2011, 02:56 PM
I moved this from another topic where it was really out of place.

Here I describe to how to make inserts for drawers etc to keep instruments such as DTIs and Mics safe when not being used.


I did not take pictures when I last made one but it is easy to make really classy looking drawer and box inserts to house treasured items.

This is what I did, as I say there are no pictures apologies about that.

First off make a shallow wooden box that is deep enough to hold your items and a neat fit inside the drawer or tool box. Thin plywood is plenty good enought for this. Drill holes, 1/4" or so at 2" grid spacing over the bottom of the box.

Get some knitted cotton as used to make t-shirts, the colour is your choice. Carefully spread this loosely over the top of the box and glue it down the sides. It must be secure and avoid wrinkles. Spray it lightly with water and set aside, you want it damp(ish) not dripping wet.

Now get your treasured items and spread them on a flat surface arranged how your prefer. Cover them with a layer of cling film but leave it slack.

Now, turn your box upside down and place it over the items and reach for your can of expanding polyurethane foam. This is the stuff they sell for filling gaps around draughty window frames etc.

Inject foam into the holes and squirt it around to ensure the space above your items gets really filled and you dont want any voids. Pretty soon it will start oozing out of the holes so slap a sheet of metal, board or whatever on and weight the whole business down. If you used thin plywood you should brace the sides as there is quite a bit of pressure exerted by the expanding foam.

Now relax, tomorrow you will have a nicely formed insert for your tool drawer (in the colour of your old t-shirt).

I specified putting cling film over the items but I have never found this necessary, and I have made a few inserts for optical items in my telescope cases, as the foam does not penetrate the knitted cotton. Dampening the fabric accelerates curing of the polyurethan and it might be what stops the foam pushing through the fabric.

Note that because the items were put on a flat surface your finished drawer insert will provide a flat top surface even when the items are in place giving the possibility of stacking inserts, but I have never done this.

Westline
03-30-2011, 03:01 PM
very cool idea .....now I know what I going to do this weekend:D
Thanks for the post

MichaelP
03-30-2011, 07:33 PM
Neat idea. It'd be nice to see how it looks.

Thank you, TAB.

randyjaco
03-31-2011, 11:17 AM
I was always under the impression that that spray foam had some nasty chemicals in it that promoted corrosion. Does any one know better?

Randy

vincemulhollon
04-03-2011, 04:50 PM
I was always under the impression that that spray foam had some nasty chemicals in it that promoted corrosion. Does any one know better?

Randy

You're probably thinking of silicone caulk that cures with acetic acid? Mostly harmless on ceramic tile, not good for steel.

Spray foam is a pretty wide term containing lots of things, but you're probably talking about isocyanate and resin stuff, supposedly inert once cured and terribly toxic until cured. Treat it like those exotic paints, where the pros wear space suits when applying it, but once it cures its not going to do much. In fact its very much like those exotic paints where you can screw around with it all day with no effect and then suddenly your body sensitizes to it and you get asthma symptoms, which is kinda a bummer.

The pro insulation guys spray it over steel electrical conduit, so best case is its nonreactive, worst case the pro insulation guys don't care.

The biggest problem I see is that stuff isn't mechanically durable, and you'll rapidly find all moving parts have little broken down bits of foam jammed in them.

The Artful Bodger
04-03-2011, 05:10 PM
You're probably thinking of silicone caulk that cures with acetic acid? Mostly harmless on ceramic tile, not good for steel.

Spray foam is a pretty wide term containing lots of things, but you're probably talking about isocyanate and resin stuff, supposedly inert once cured and terribly toxic until cured. I said use polyurethane foam


Treat it like those exotic paints, where the pros wear space suits when applying it, but once it cures its not going to do much. In fact its very much like those exotic paints where you can screw around with it all day with no effect and then suddenly your body sensitizes to it and you get asthma symptoms, which is kinda a bummer.

The pro insulation guys spray it over steel electrical conduit, so best case is its nonreactive, worst case the pro insulation guys don't care.

Like I said, it is polyurethane foam and is chemically inert when reacted, the only danger to health is that it might stick to careless fingers and whatever hazard there is from the hydrocarbon propellant which drives it from the can. Dont burn the foam.


The biggest problem I see is that stuff isn't mechanically durable, and you'll rapidly find all moving parts have little broken down bits of foam jammed in them.
Errrrr...ummm..... thats what the t-shirt fabric is all about.:(


N.B. Dihydrogen monoxide can be used to hasten the reaction but be especially carefully handling this stuff, not only does it cause corrosion but it can cause death if inhaled.

mike os
04-03-2011, 06:10 PM
Dihydrohen monoxide is serious stuff dude, highly corrosive, destructive and kills thousands every year, causes serious habitat destruction and cost billions every year to deal with... should be avoided at all costs

Elninio
04-03-2011, 08:25 PM
I should have seen your thread, we're on the same page. d'oh!

Bill736
04-03-2011, 10:14 PM
To avoid the hazards of dihydrogen monoxide, I suggest using hydrogen hydroxide.

RKW
04-03-2011, 10:44 PM
Nice idea.

Might I suggest it for an article (one page or so) for the HSM mag? If you don't have time maybe a few pictures to this thread?

Black_Moons
04-03-2011, 10:52 PM
dihydrogen monoxide ravaged japan recently and nearly caused the reactors to melt down -_-;

The Artful Bodger
04-04-2011, 01:22 AM
Nice idea.

Might I suggest it for an article (one page or so) for the HSM mag? If you don't have time maybe a few pictures to this thread?

It just so happens that I do need to make a couple more inserts in the near future, I could have started one today but have none of the foam.. maybe when the environmental oxidane levels subside.....

mike os
04-04-2011, 02:32 AM
dihydrogen monoxide ravaged japan recently and nearly caused the reactors to melt down -_-;

although oddly enough the exact same product is used to prevent just that eventuality:eek:

Elninio
04-04-2011, 05:58 AM
The foam you used, is it brittle?

The Artful Bodger
04-04-2011, 06:09 AM
The foam you used, is it brittle?

It feels quite firm under the fabric.