Topic: Undercoat????? (Read 16830 times)

bigfella · « **on:** March 15, 2007, 10:01:18 am »

Hi All

I am just about to the stage of painting my Higgins PT Boat. The boat is of Balsa contruction which I have had Fibre glassed on the Hull and a coat of resin on the deck. I want to paint the boat with a brush using Humbrol paint #126 US Grey (i think) which is a satin finish and #174 Red also satin for the underside. I want to use satin as I have seen some boats this size with Matt and they don't look right as with Gloss it makes it look sort of plastic, but what do I know.

What I want to know is as I am going to paint about 3 coats do I have to use a primer or undercoat first?? As the only brush on undercoat I can find is Humbrol #1 and it looks just like a matt version of the grey paint I am going to use???????

Please help a novice

Regards Bigfella

RickF · « **Reply #1 on:** March 15, 2007, 10:18:07 am »

I always use Halford's spray-can primer, which is available in grey. Nothing to stop you using spraying for the undercoat, followed by brush painting.

Rick

bigfella · « **Reply #2 on:** March 15, 2007, 10:25:49 am »

Hi Rick

I dont think that Halfords is available in Australia. The only spray undercoat I can find is Tamiya and that is, i believe, not compatible with Humbrol enamel as it is ment for plastic cars and the like.

Regards Bigfella

DickyD · « **Reply #3 on:** March 15, 2007, 10:31:02 am »

Hi Bigfella
All I used on my Schuetze was grey and brown primer varnished with matt varnish.
Works for me.

Richard

RickF · « **Reply #4 on:** March 15, 2007, 12:53:21 pm »

Sorry Bigfella -forgot where you live.

Don't you have an equivalent to"Halfords" car accessory shops over there? I know you have cars, 'cos the DSM watches "Neighbours"! Any modern (non-cellulose) grey primer should do.

Rick

Colin Bishop · « **Reply #5 on:** March 15, 2007, 12:54:17 pm »

Bigfella - don't you have shops that sell car paints over there? You should find that the primers are acrylic and essentially the same as the ones we get in Halfords. Mind you, the instructions say turn can upside down to clear the nozzle which might be a bit confusing for you antipodeans!

Colin Bishop · « **Reply #6 on:** March 15, 2007, 12:54:58 pm »

Snap!

RickF · « **Reply #7 on:** March 15, 2007, 01:02:50 pm »

I won! I won!

chromedome · « **Reply #8 on:** March 15, 2007, 01:42:02 pm »

Rick?...would you say that Halfords spray undercoat is OK used straight on to bare wood?

chromedome

Shipmate60 · « **Reply #9 on:** March 15, 2007, 01:45:27 pm »

Chromedome,
For wood I usually use normal household undercoat/primer.
Rub down well and apply 3 coats then Humbrol on top.

Bob

chromedome · « **Reply #10 on:** March 15, 2007, 01:50:22 pm »

Hi Bob...I was thinking of using thin dope?

chromedome

Colin Bishop · « **Reply #11 on:** March 15, 2007, 01:50:45 pm »

I normally use one of the quickdry waterbased primers as a base or a grainfillers such as sanding sealer.

RickF · « **Reply #12 on:** March 15, 2007, 04:27:11 pm »

Bob,

I usually give bare wood - especially balsa - a coat of dope or sanding sealer (dope and talcum powder) followed by a rub down before spraying. Seems to work.

Rick

Shipmate60 · « **Reply #13 on:** March 15, 2007, 05:42:24 pm »

Sanding sealer or thin Epoxy Resin will harden and set the hull I agree, but the question was about undercoat.

Bob

DickyD · « **Reply #14 on:** March 15, 2007, 06:10:58 pm »

Epoxy resin then primer then varnish. That'll do it.

Richard

sinbad · « **Reply #15 on:** March 15, 2007, 06:33:19 pm »

I use plenty of the grey primer anyone know of a cheep supply.
Sinbad.
(New member)

DickyD · « **Reply #16 on:** March 15, 2007, 08:13:32 pm »

Quote from: sinbad on March 15, 2007, 06:33:19 pm

I use plenty of the grey primer anyone know of a cheep supply.
Sinbad.
(New member)

Check out Amazon for aerosol paints.
Their primer is £3.39 a tin for 400ml. Same size as Halfords.
Even with the postage you only have to buy 2 to save money.
Its what I am using on my build.
Don't know what your Halfords is like but we have two here who very rarely have the Plasticote in stock. This is as good.
Go on Amazon, type in spray paints in the search box. The primer is on the second page.

Richard

bigfella · « **Reply #17 on:** March 15, 2007, 09:57:26 pm »

Thanks Guys

I did not know that I could use Auto Primer. I will check one of the car places such as Super Cheap or Auto Barn or even Repco for a primer that is suitable for an Enamel top coat. I was under the assumption that an Acrylic undercoat would not mix with an Enamel top coat. Is this correct????

Regards Bigfella

Stavros · « **Reply #18 on:** March 15, 2007, 10:49:18 pm »

Right what you need is quite simple any sprayable undercoat will be OK for enamel based paint,it is when you allready have enamel on your boat and try to overcoat with either acrylic or cellulose that the pr-obs begin.If you are priming Whit an auto primer why don't you get the hull colour in aerosol and spray tehat as well you will get a far superior finish than brush painting any probs pm me stavros

Colin Bishop · « **Reply #19 on:** March 15, 2007, 11:01:39 pm »

Stavros is our resident expert - heed his words!

bigfella · « **Reply #20 on:** March 15, 2007, 11:17:21 pm »

Hi All

Thanks for clearing that up Stavros, I knew it was something like that but did not know which way around. I will give it a go with spray, Any ideas of which spray is best for topcoat IE that matches the colours for a PT Boat in a satin finish.

Regards Bigfella

Bunkerbarge · « **Reply #21 on:** March 15, 2007, 11:17:46 pm »

Without wanting to hijack this thread but on a very similar topic as is being discussed I have just coated a hull with a painted on coat of fibreglass resin.

When it had set I sprayed a coat of Halfords grey primer and the paint cracked as it dried to the point where it has opened up and looks as though it is incompatable with the resin.

I would have expected Halfords acrylic primer to go straight on to resin without a problem as this is a common requirement for car body repairs but this is not the first time I have experienced this problem. I tried a coat of Humbrol enamel over it as well and that has now all cracked up also so it looks like I am faced with a complete strip down.

Anyone any suggestions, particularly as to how the hell do you remove fibre glass resin from a wooden hull?!! I was going to try Nitromors but this project is one step away from the bin at the moment.

Shipmate60 · « **Reply #22 on:** March 15, 2007, 11:24:33 pm »

Bunkerbarge,
You know ther is only one way to remove it all safely, elbow grease and wet and dry.
This is the reason I use household primer undercoat brushed on thinly for the first coat.
Some Halfords Primer is still celulose based so will react.

Bob

Colin Bishop · « **Reply #23 on:** March 15, 2007, 11:31:14 pm »

Bunkerbarge - did you use polyester or epoxy resin? Could make a difference. It may be necessary to "passivate" the resin surface before applying further coatings. I'm not an expert on this but no doubt others will be able to advise.

Bunkerbarge · « **Reply #24 on:** March 16, 2007, 09:25:36 am »

Quote from: Colin Bishop on March 15, 2007, 11:31:14 pm

Bunkerbarge - did you use polyester or epoxy resin? Could make a difference. It may be necessary to "passivate" the resin surface before applying further coatings. I'm not an expert on this but no doubt others will be able to advise.

I've never heard of that expression before, thanks Colin.

Looks like a bit of reasearch is required.

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Author Topic: Undercoat????? (Read 16830 times)

bigfella

bigfella

sinbad

bigfella

Stavros

bigfella