Technical question on Paint

[MASH]

My repairer is talking about using automotive Acrylic paint instead of "linear polyeurathane". What is Linear Polyeurathane, and is he correct in saying it can't be patched/ Why not?

And will Acrylic car paint last much less than LP?

Finally, is there a marine pait that will not fade and can be patched in future, or am I better going for the auromotive stuff? Colour is aquamarine blue.

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by MASH on 23/06/2004 18:57 (server time).</FONT></P>

 

[Anthony]

u might want to chat to International Paints tech support. Ok they are going to be biased towards there own paint, but they do seem to know what the are talking about, and were very honest with me with regards to the limitations of their paints for the job I was intending. Just might give you some more info to go on.

Anthony

<hr width=100% size=1>The difference between men and boys, is just the price of their toys...

 

[Joe_Cole]

Never heard of Linear Polyurethane and I worked for a Manufacturer of Car Paints for many years. Unless it's a new development it sounds like *****hit, though I'd be happy to be proven wrong. It may be that "linear polyurethane" is a term which someone has coined for so called single pack polyurethane. This is paint which contains a bit of polyurethane but is not a true 2 Pack polyurethane. If it is a single pack then I would expect it to have similar durability to an ordinary Acrylic paint. If it is a two pack polyurethane then it will be much more durable....and also much more expensive.

I've never come across a car paint that can't be repaired, though colour matching is frequently a problem. It may be that your painter is trying to put you off using a two pack material as it isn't quite so easy to apply (Health and Safety equipment is needed and it needs the right temperature to "go off")

Fading is mainly due to the action of UV on the pigment in the paint. Red, for example, is notorious for fading. Blue is better, but it can be a problem. Make sure that whatever you use that you get the full details of the colour. (Manufacturer, paint type, colour reference number) Believe it or not there will be dozens of "Aquamarine Blues"; you will want to know exactly which one has been used for future reference.

Joe



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[sailorman]

AWLGRIP is the only paint system worth concidering I.M.H.O

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[ex-Gladys]

We have an invoice for AMber being acrylic painted in 98. Quick wash off and she looks great. There are one or two spots where the paint is coming away around fittings, and one or two "wear marks" where the paint has been dinged, but I would certainly go back to the guys who did her then and ask for "another one of those please"

<hr width=100% size=1>Larry Botheras

Anderson 26 "Amber"

 

[steve28]

I had mine sprayed in awlgrip in a field on a damp day, the results were absolutley brilliant, i can read a book in the reflection from four feet away !

and its durable its been on for four years now, one chip from the anchor but that was easy to sort.

steve


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[MainlySteam]

The top marine polyurethane paints such as Interspray 900 are linear polyurethanes (long linear molecules) and you will find them described as such in the manufacturers' application data. They can be patched but, as far as I know, the computerised colour matching systems available for automobile paints (which I think may be based on pigment additions rather than paint mixing) do not exist for them so patches may be slightly different - if they do exist they are not often used. If white and the manufacturer's same white is later used for a patch have never found it a problem but I have known superyachts get entirely repainted for the sake of looks after a ding on one side. Against that linear polyurethanes are resistant to dings on account of their hardness. As with most good things they are the most expensive for up front material and application cost but are long lived and are always the product of only choice for high quality vessels.

I would personally stay away from automotive products on a boat - it may be that they are acrylic polyurethanes (I would not know) but in any event if going to an acrylic polyurethane, which are also manufactured for marine use, I would personally stick with one from a reputable marine paint manufacturer the names of some of which have already been mentioned. In any event, the acrylic polyurethanes are inferior to the linear ones.

John

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[oldsaltoz]

G'day Mash,

Linear Polyurethane such as International's Interspray 900 has long chain polymers that give the product excellent self levelling qualities; the finish is hard and fine that like glass you can not draw in with a pencil.

It will last for many many years and look very nice, it is expensive and is best applied with two mist coats and a final full coat after letting it stand for 10 minutes after mixing, dries very fast and must be applied in low humidity, less than 74% I think.

I got an automotive paint shop pro to paint a transom extension I did for a client a couple of years ago, he looked at the sanded area and said I would have to re-sand them as the finish was not smooth enough; I had finished with an 80 grit, he wanted me to use 200 grit. I told him to apply the paint as is and he was blown away by the fact NO sanding marks were viable when the final coat was applied. he even looked at painting some vehicles with it as it would save him some 4 hours of fine sanding.

In some applications the 900 can be applied with a brush and look like it has been sprayed, such are the self levelling qualities. needless to say I swear by the stuff; it's a commercial grade and may be difficult to procure, but keep looking, it is available.

And, no, I have no connection with International or any other coatings manufacturers or distributors, just enjoy using good products.

Avagoodweekend.......



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.