chrisf
|
| posted on 1/11/04 at 07:00 PM |
|
|
Crazy seat making idea
I made a rough seat out of MDF and checked for fitment in my locost. I fit in it pretty well and have a bit of space in the critical areas such as
legs, ribs and shoulders. I have this plan...
I want to fill the MDF seat with drywall mud, plaster of paris, etc. I will then plop into the seat and have a good read for an hour or so. When I get
out, I should have a nice form of my backside. Then I will sand it, bondo it and finish it like any other FRP/CPRF mould.
I know the proper way is to use a2 part poly U foam, but this should produce the same results for a 1/3 or the coast. Does anyone have any opinions on
this?
--Thanks, Chris
|
|
|
|
|
David Jenkins
|
| posted on 1/11/04 at 07:07 PM |
|
|
Chris,
Have you ever been in intimate contact with gypsum plaster, plaster of paris, etc. while it's setting? (Oooer missus! ). It gets VERY hot!
I remember trying to make a cast of my hand when I was a kid, using plaster of paris - had to give up half-way to setting, as I couldn't stand
the heat. Now imagine sitting in several pounds/kgs of setting plaster!
You might get away with letting it half-set, and then sitting in it...
rgds,
David
|
|
|
chrisf
|
| posted on 1/11/04 at 07:28 PM |
|
|
No, I have no experience with the stuff. At our local home improvement store, though, I saw some in a plasitc bag. It plastic-like and not hot at all.
I did wonder if it would go off when it came in contact with the air.
So it is not a good idea? Once I pop out of the seat, will it cure withing a few day?
|
|
|
Tralfaz
|
| posted on 1/11/04 at 07:41 PM |
|
|
The plaster in thick applications will crack and shrink unevenly.
2 part polyutrethane kits are available for 40 dollars (US). Not too bad in my mind....
Good Luck,
Brian
Ps Otherwise try carving one out of rigid foam board...
|
|
|
David Jenkins
|
| posted on 1/11/04 at 08:18 PM |
|
|
quote:
Originally posted by chrisf
No, I have no experience with the stuff. At our local home improvement store, though, I saw some in a plasitc bag. It plastic-like and not hot at all.
I did wonder if it would go off when it came in contact with the air.
Once you mix it with water, it's an exothermic reaction. Easy to try it - take a plastic drinking cup, make a thick runny paste of plaster of
paris and pour it in the cup. Now hold the cup.
I go with Brian's suggestion - get some polyurethane foam sheet (builder's merchants), glue it roughly into shape, then carve it with
knives, sandpaper, rasps, etc. Very easy, but very dusty. If you make a mistake, just glue on some more sheet and try again.
Once you've finished you can glass-fibre straight over the top if you like, either to make a finished seat, or to make a buck as the basis of a
mould.
Just thinking off the top of my head - may be complete rubbish! 
rgds,
David
|
|
|
jacko
|
| posted on 1/11/04 at 08:50 PM |
|
|
seating
HI David fiber glass will melt polyurethane -polystyrene you would have to seal it with body filer or some thing first ? jacko
|
|
|
David Jenkins
|
| posted on 1/11/04 at 09:02 PM |
|
|
Polystyrene will melt - polyurethane doesn't (it's what's used as the core for surfboards).
|
|
|
jacko
|
| posted on 1/11/04 at 09:08 PM |
|
|
David
ok im corrected
jacko
|
|
|
andyps
|
| posted on 3/11/04 at 01:25 PM |
|
|
Try using the expanding foam filler sold in DIY shops instead. Sit on a bin bag and squirt some foam into it - it expands by 30 times so one can would
probably be enough for a seat.
Andy
An expert is someone who knows more and more about less and less
|
|
|
chrisf
|
| posted on 3/11/04 at 02:23 PM |
|
|
Good stuff all! I ended up buying the two part pourable foam. I figured that I might as well do it properly.
--Thanks for the help all, Chris
|
|
|
David Jenkins
|
| posted on 3/11/04 at 02:39 PM |
|
|
Make sure that you're well wrapped up when you pour it - overalls, no bare skin, etc. - you DON'T want to get that stuff on you while
it's frothing and setting. Not only does it get very warm, it sticks like the proverbial to the blanket, so if get some on you you can't
get it off in a hurry!
There's a famous out-take of a Tomorrow's World presenter (Judith Hahn?) doing a demo of this stuff, and it went over the side of the
beaker and onto her hand - she had to stop the live presentation and hand over to someone else as it was starting to burn her.
Perhaps someone here knows the correct way to do this... I've seen films of the F1 teams fitting out a car, and they have the driver sitting on
a plastic bag while someone pours the mix in the top. Must get warm round his bum!  Perhaps they wear their nomex undies while they're doing
it.
David
|
|
|
ned
|
| posted on 3/11/04 at 03:16 PM |
|
|
I know you can get these seat bags that contain a load of polystrene type balls (like packaging stuff) you then pour something in to act as a catalyst
and sit on it in situe and it sets off quite quickly in much the same fashion as already described.
Ned.
beware, I've got yellow skin
|
|
|
Viper
|
| posted on 3/11/04 at 10:41 PM |
|
|
another option for foam is boat shops, you can buy the two chemicals to make the foam, it is used as bouyancy for canoes, sailing dinghys etc
etc...
just a thought
|
|
|
chrisf
|
| posted on 4/11/04 at 12:11 AM |
|
|
Yep, that is what I ended up buying. I had to order the stuff from a composite shop, though. I have a lake near me with a marina, but no such luck.
I'll post the pics on my website as the seat progresses.
--Chris
|
|
|
Jermyn
|
| posted on 4/2/05 at 04:42 PM |
|
|
quote:
Originally posted by andyps
Try using the expanding foam filler sold in DIY shops instead. Sit on a bin bag and squirt some foam into it - it expands by 30 times so one can would
probably be enough for a seat.
Has anyone completed this since the last post? I was going to try it with plaster of Paris. But, I don't want to burn my arse
This idea with the spray-can insulation foam seems like a good idea. But will it melt a plastic bag? Plus, Ive gotten this stuff on my hands before
and it'sreally nasty stuff.....sticky, gooey and irritating.  It takes solvent to get it off.
Also, whats the setting time for this stuff? How long are you going to have to sit there?
I really want to try this and I think it could be done cheaply. If anyone has done this please post some pics of how it came out and your sources for
the foam or whatever you used
Thanks
If life is a race do you want to be the first one to finish?
|
|
|
chunkielad
|
| posted on 4/2/05 at 07:33 PM |
|
|
WEAR GOGGLES!!!!!
I got some of this in my eye once when the nozzle squirted back when filling a gap - I needed to be put to sleep so they could surgically remove it!!!
They also said it is alkaline which means it doesn't stop burning even when set. Luckily, they fixed me but PLEASE BE CAREFUL!!!
|
|
|
Jermyn
|
| posted on 4/2/05 at 08:59 PM |
|
|
quote:
Originally posted by chunkielad
WEAR GOGGLES!!!!!
I got some of this in my eye once when the nozzle squirted back when filling a gap - I needed to be put to sleep so they could surgically remove it!!!
They also said it is alkaline which means it doesn't stop burning even when set. Luckily, they fixed me but PLEASE BE CAREFUL!!!
Poor Chunkie. Had to be put to sleep and got fixed all in the same trip
Thanks for the heads up.
If life is a race do you want to be the first one to finish?
|
|
|
NS Dev
|
| posted on 6/2/05 at 10:10 AM |
|
|
I thought about using the aerosol foam, then found that the proper 2 pack stuff is actully cheaper than the equivalent volume of foam from Screfix in
aerosol form!
try - http://www.cfsnet.co.uk/
|
|
|
chrisf
|
| posted on 7/2/05 at 02:51 PM |
|
|
Jermyn:
I decided not to do this. I do have the 2 part foam that is unopended going spare. U2U if you are interested in the stuff.
I planned on making the seats in CFRP. When I did the math, I figured out that I can get full carbon Tillett seats for similar money.
--Chris
|
|
|
mangogrooveworkshop
|
| posted on 7/2/05 at 03:11 PM |
|
|
quote:
Originally posted by andyps
Try using the expanding foam filler sold in DIY shops instead. Sit on a bin bag and squirt some foam into it - it expands by 30 times so one can would
probably be enough for a seat.
The expandable stuff from the can doesnt set well if its not able to contact the air.
The twopack is much better at this job and costs less than screwfix stuff in larger quantities.
|
|
|
Rob Lane
|
| posted on 7/2/05 at 03:21 PM |
|
|
Just an aside, whilst I was in wreckers looking for a spare ecu I came across a good condition Toyota Carina.
Good that is until you saw the inside, the driver had a can of expanding foam on passenger seat which exploded !
The whole of the car was covered except for a pattern of the driver, just like a sillouette. The foam had stuck to everything, the glovebox was
sealed up by it along with the seatbelt on passenger side.
The roof and seat looked just like an explosion pattern !
What a mess.
|
|
|
stephen_gusterson
|
| posted on 7/2/05 at 10:45 PM |
|
|
I wonder how he filled the bit in the insurance claim form that asks for a drawing of the accident 
atb
steve
|
|
|
NS Dev
|
| posted on 7/2/05 at 11:34 PM |
|
|
|
|
|
mangogrooveworkshop
|
| posted on 8/2/05 at 12:24 AM |
|
|
And playing on the radio was Stuck on you by MR L Ritchie There is a can of this stuck in the side of the building at work.
This huge buble of foam greets you with the orange can firmly implanted!!!!!!
|
|
|
Liam
|
| posted on 8/2/05 at 12:40 AM |
|
|
This is exactly what my mate did for his MR2 track car!!
Made a wooden base and back that fit in the car - just two bits of ply. May have had some sides for containment too.
Prepared some black bin liners (maybe used two joined together I think). Put some blocks of wood in so holes would be left for the seatbelts.
Sat in perfect driving position on the bin liners.
Filled with expanding foam.
Waited an hour or so...et voila!!
Rathe than making a mould or anything silly like that, he trimmed it all in a layer of black gaffer tape. And there you have one superbly comfortable
seat that is removable in seconds. If you wanted it to look nice you could shave it about, fit some sponge in and trim it with fabric/vinyl/leather
but it's for the track so he didn't bother.
The foam is literally zero thickness at the base (which is on the car floor) as the whole idea was to allow this 6'7" guy to comfortably
drive a MK1 MR2 with a helmet and a roll cage. But because the foam is supporting every square inch of you it doesn't feel like you're
sitting on a hard base at all. It's apparently incredibly comfy!
I could try and get some photos if anybody is interested. Also I think it took a bit more than 1 can of foam. That stuff never expands as much as it
says.
Another bonus is that i can do exactly the same in his car and make a removable seat for me to drive it too! Oooh that actually reminds me it was
done in two parts - base and back in separate bags - but still done at the same time.
I have my poncy Cobra Roadster Sevens for pimpin, but will be making a set of removable foam seats for me and my friends so we can swap in seconds for
track day driving and all be in perfect comfort dispite the 5'5" to 6'7" height range (adjustable pedal box and steering
column will help here too!).
Hope that inspires!
Liam
|
|
|
