MattWatson
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| posted on 5/1/03 at 06:46 AM |
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Building plugs.... to bondo or not to bondo?
Well, I am at a point where I am going to be laying a mould on a nosecone I built... Now, I have done all of my work with drywall putty, and was
wondering, can I add wax right overtop, or do I really NEED bondo?
It would shure be cheaper if I didn't 
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interestedparty
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| posted on 5/1/03 at 07:47 AM |
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Sounds to me like what you need here is a good quality paint system, something that will fill all the microscopic holes in the surface of the plug,
and also thick enough to allow smoothing with wet and dry paper til the surface shines.
I think I would use car primer and primer/filler to start, then some black gloss
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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MattWatson
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| posted on 5/1/03 at 07:05 PM |
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quote:
Originally posted by interestedparty
Sounds to me like what you need here is a good quality paint system, something that will fill all the microscopic holes in the surface of the plug,
and also thick enough to allow smoothing with wet and dry paper til the surface shines.
I think I would use car primer and primer/filler to start, then some black gloss
John
I can get the putty smoth enough, just people like AlanB and such always add the bondo on top of the drywall putty, and I am wondering if there is a
reason for it?
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Alan B
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| posted on 10/1/03 at 11:39 PM |
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A few reasons.
If you paint on top of Bondo, you can rub through the paint when wet sanding without a problem, but do the same on drywall filler and the water
attacks it.
You can get a good shine on the Bondo to check your surface quality even before paint....the drywall filler will always be dull.
Bottom line: If you can get your drywall filler surface good enough, and not rub through your paint, then in theory you don't need Bondo.
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MattWatson
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| posted on 12/1/03 at 10:34 PM |
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Thanks. Thats exactly what I wanted to know. So basically, just do as thin a coat of bondo as possible?
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Alan B
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| posted on 14/1/03 at 01:04 PM |
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Yes it can be very thin as long as your drywall filler is very true.
The trouble is if you go too thin you can rub through easily, and it takes just as long to sand if it is 1/16" thick or 1/8" think....the cost of
Bondo is the main issue.
I have used 7 one gallon tins so far, about 80/90 dollars worth.
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Alan B
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| posted on 14/1/03 at 01:25 PM |
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Matt, here is a piece of my plug, from when I cut through the front to shorten it.
You can see the Bondo here is about 40 to 50 thousandths thick (1/16" tops)...OK on a flat or smooth area...bit thin in corners or edges.
HTH, Alan.
 
plug section
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Alan B
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| posted on 4/4/03 at 01:36 AM |
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Matt, I think I'm going to try without Bondo.....as I said ealier...
"Bottom line: If you can get your drywall filler surface good enough, and not rub through your paint, then in theory you don't need
Bondo."
So basically I need to get it as true as I can before paint so I dont need to do much to the paint and rub through......I diid find that (to my
surprise) that you could sand the drywall filler with 320 grit and not clog....so I've done this and tried paint in a few areas.....so we shall
see how it goes....
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Nick Davison
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| posted on 4/4/03 at 08:51 AM |
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Alan
I am virtually in the same position with a nosecone as Mat, although I have modified an existing cone. To aid release I have sprayed the cone with
Polyurethane paint which is, apparently 100% release for GRP.
Have you used this medium before and do you think I will encounter any problems.
Nick
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stephen_gusterson
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| posted on 4/4/03 at 09:16 AM |
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Bondo is what exactly?
Im about to do my second moulding (once I get the friggin first one sorted).
This one is shaped by MDF, hardboard and body filler. Im going to use a sealer, summat like wood varnish, sanded down.
I MIGHT put wax on it - but after my first experience it seems its designed purely to repel the PVA - which is no massive suprise if you look at a
newly polished car in the rain.
I think the PVA might seperate on its own over a sealed varnished surface.
But Bondo......whats that in the scheme of things?
atb
steve
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Alan B
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| posted on 4/4/03 at 01:10 PM |
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Bondo - Sticky grey shite, with red hardener...turns pink when mixed
Can't remember UK brand names...but it's just regular polyester car bodyfiller..nothing special
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Alan B
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| posted on 4/4/03 at 01:19 PM |
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quote:
Originally posted by Nick Davison
Alan
I am virtually in the same position with a nosecone as Mat, although I have modified an existing cone. To aid release I have sprayed the cone with
Polyurethane paint which is, apparently 100% release for GRP.
Have you used this medium before and do you think I will encounter any problems.
Nick
Hi Nick, no I haven't used poly U paint. I do know you have to be very careful with some paints as they aren't as cured as they appear. If
it says it is suitable then you should be OK though.....just be sure to wax as per the tin's instructions and apply as even a coating of PVA as
possible.
In my scenario I'm using the same paint (Kilz - don't know if there is a UK equivalent), the same wax and the same PVA..so I should be OK
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Nick Davison
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| posted on 4/4/03 at 01:38 PM |
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You said in an earlier post that you are painting the body once out of the mold. What type of primer and top coat are you using? Also is it suitable
for ali so I can prepare my complete car and spray all at once?
Nick
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Alan B
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| posted on 4/4/03 at 06:26 PM |
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Nick, I have no idea what the paint will be to be honest.....
If I do myself it will have to be something that can be post finished..(cellulose?)..as I can't guarantee a lack or runs or dust (do my best of
course...just planning for sod's law)
If I pay to have it done, then I'll let them advise me as to the best.
Back to your question, I'm certain that there will be a primer and paint to suit both Ali and GRP...may be a pre-treatment for the Ali
perhaps?
Good question for Chris G perhaps......
Or his brian in a jar at least...
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chrisg
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| posted on 4/4/03 at 08:03 PM |
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Bubble, bubble, bubble.....
If you stick to the same paint manufacturer throughout then they will have compatible etch primer for GRP and Ali, with some this will be one for both
and others you will need one for GRP and a different one for ali, but sticking to the same manu. will guarantee that the top coat works with the
primer(s).
The other thing is that paint is one of those things that you get what you pay for, cheap paint is false economy, buy the best you can afford - I use
Sikkens
Cheers
Chris
Note to all: I really don't know when to leave well alone. I tried to get clever with the mods, then when they gave me a lifeline to see the
error of my ways, I tried to incite more trouble via u2u. So now I'm banned, never to return again. They should have done it years ago!
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stephen_gusterson
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| posted on 4/4/03 at 10:56 PM |
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Are you the same Chris that told me he got his paint free ans it was the blue they used on local buses?
atb
steve
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chrisg
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| posted on 4/4/03 at 11:21 PM |
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I said I used Sikkens - I didn't say I paid for it!
Cheers
Chris
BTW the buses are purple now - what bloody good is that?
Note to all: I really don't know when to leave well alone. I tried to get clever with the mods, then when they gave me a lifeline to see the
error of my ways, I tried to incite more trouble via u2u. So now I'm banned, never to return again. They should have done it years ago!
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stephen_gusterson
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| posted on 5/4/03 at 11:16 PM |
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ya could mix a bit of white with it and get pink....would that suit?
Will have to make a decision on my colour in next few months. There is a nice 'old fashioned' dark non met red on Audi TTs I like the look
of.
atb
steve
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Nick Davison
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| posted on 6/4/03 at 08:22 PM |
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Chris
I take it that Sikkens is liable to be expensive, although you don't pay for it (which is admirable).
What type of paint is it, acrilic etc (I know little of paint) and what pressure will it need to be sprayed at as at the moment I only have a HP
gun.
Also do you have a contact who retails it other than the web site.
Nick
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Viper
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| posted on 6/4/03 at 08:25 PM |
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quote:
Originally posted by Alan B
Bondo - Sticky grey shite, with red hardener...turns pink when mixed
Can't remember UK brand names...but it's just regular polyester car bodyfiller..nothing special
sounds like isopon p38 body filler??
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chrisg
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| posted on 6/4/03 at 08:56 PM |
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It's Two-pack, which, is *supposed*to be unobtainable if you're not in the trade, although people on here have been able to get it.
Problem is that it's very poisionous (isocyanates)and shouldn't be used without an air fed mask and the proper extraction
facilities. also you'd need a 14-20 cfm commpressor for best results.
For home use I'd recommend Cellulose, it needs very good preparation but isn't any where near as dangerous as two-pack. You could spray
it quite suceessfully with a hp gun as it can be flatted and polished,a HVLP gun would be better.
Acrylic is not popular these days, it gives a very "toffee apple" finish but is not very durable, hence it's use in cheap banger
blow-over jobs
Cheers
Chris
Note to all: I really don't know when to leave well alone. I tried to get clever with the mods, then when they gave me a lifeline to see the
error of my ways, I tried to incite more trouble via u2u. So now I'm banned, never to return again. They should have done it years ago!
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Alan B
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| posted on 6/4/03 at 11:15 PM |
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Viper - Yes, that rings a bell, just regular body filler..glad you interpreted my very technical description....
Chris - "toffe apple"....is that good?
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Nick Davison
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| posted on 7/4/03 at 10:04 AM |
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Chris
I thought that cellulose had some implications when used on GRP?
Nick
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Spyderman
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| posted on 7/4/03 at 11:35 AM |
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Cellulose is fine on GRP, as it is on most materials.
Just make sure you prime well and etch prime any Ali.
Terry
ps. Only time you might have problems is when it is applied over Polyurethane or other such materials.
[Edited on 7/4/03 by Spyderman]
Spyderman
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