mothman505

Epoxy brand compatability

Recommended Posts

I'm coating the hull of a Snipe with a brand of epoxy called Marine Guard 8000 with microballons to fair the hull.  What if I use another brand like West System to apply the 4 oz.cloth....?

I have glassed the rudder with the 8000 and although it is slow drying resin, it seems to work well.

Should that cause a problem ?

Share this post


Link to post
Share on other sites

I think all epoxies bond to each other fine. Pre-thickened fairing epoxies make it difficult to mix resin & hardener thoroughly. Lots easier to mix the epoxy first and them mix in the desired fillers.

Share this post


Link to post
Share on other sites
47 minutes ago, Russell Brown said:

I think all epoxies bond to each other fine. Pre-thickened fairing epoxies make it difficult to mix resin & hardener thoroughly. Lots easier to mix the epoxy first and them mix in the desired fillers.

The first application was 100% epoxy.  Then, once dry,  the epoxy with the microballons was applied and sanded.

Share this post


Link to post
Share on other sites

As you will be relying on a mechanical bond ensure your surface preparation is done properly, well sanded and acetone wiped prior to laminating. Properly mixed cured epoxy is inert and will not react with other epoxies, it may however inhibit the curing of most polyesters.

  • Like 1

Share this post


Link to post
Share on other sites

Unless the first epoxy was "amine blush free" - start with a wash of water and a little soap - rinse well.  You cannot sand amine blush away.

Share this post


Link to post
Share on other sites
14 minutes ago, Blitzen said:

Unless the first epoxy was "amine blush free" - start with a wash of water and a little soap - rinse well.  You cannot sand amine blush away.

Mild powdered dish detergent, rinse that with borax water mix, followed by fresh.  Do that before sanding! Amines don't stand a chance.

  • Like 1

Share this post


Link to post
Share on other sites

Amine blush comes off with a damp rag. Rinsing the rag in a bucket often is good too.

Share this post


Link to post
Share on other sites

I've used different brand epoxies for laminates vs fillers. As I have assorted resins and hardeners from a handful of different brands but none resin and hardener from the same, I'm thinking about doing some testing to see if a like ratio mix resin will kick with a different brand (but same ratio) hardener.

Share this post


Link to post
Share on other sites
16 hours ago, Russell Brown said:

Amine blush comes off with a damp rag. Rinsing the rag in a bucket often is good too.

Why use water when you can break out the acetone!?

But I agree - straight water works great. I sometimes use a scotchbrite pad, but no need for any chemicals.

Share this post


Link to post
Share on other sites
On 12/14/2020 at 11:06 AM, Blitzen said:

Unless the first epoxy was "amine blush free" - start with a wash of water and a little soap - rinse well.  You cannot sand amine blush away.

The amine free stuff is marketing 

don’t believe it , if it’s an amine epoxy always wipe down with water 

Share this post


Link to post
Share on other sites

We’ve been using Simple Green in water with a green scotchbrite for amine. The blush free is more like brush less. Less is less to wash off.

 

 

Share this post


Link to post
Share on other sites

Regarding acetone- this comes from WEST 

There is no good reason to wipe a surface with an organic solvent unless there is evidence that an organic contaminate is present on the surface. We are all familiar with solvents like acetone, lacquer thinner and proprietary mixtures like DuPont Prep-Sol™ formulated to remove specific contaminants. Most solvents of this type will remove organic contaminants such as oil, grease, wax, etc. Wiping a surface with an organic solvent may seem like a great idea, but these solvents may dissolve contaminates from rags and deposit them on the work surface where they can prevent epoxy adhesion. This is not a good practice for surface preparation. Silicone is a well-known mold-release agent and incidentally an ingredient in many home laundry fabric softeners. A surface can get contaminated by the silicone that the organic solvent extracts from a wiping rag. Many organic solvents can dissolve the man-made fibers found in rags. An acetone wipe down can deposit plastic on the surface you are trying to clean. These dissolved plastics can act just like a mold release, which is the opposite of surface preparation for good epoxy adhesion.

  • Like 2

Share this post


Link to post
Share on other sites

Thanks for posting that. To me the best surface for bonding to is a freshly sanded surface. I use lint-free paper towels (like mechanics use) to scrub the dust from the surface until there's no dust showing on the towels. Flushing with water (with a little scrubbing) is obviously best for removing dust.

Share this post


Link to post
Share on other sites
6 hours ago, cyclone said:

Regarding acetone- this comes from WEST 

There is no good reason to wipe a surface with an organic solvent unless there is evidence that an organic contaminate is present on the surface. We are all familiar with solvents like acetone, lacquer thinner and proprietary mixtures like DuPont Prep-Sol™ formulated to remove specific contaminants. Most solvents of this type will remove organic contaminants such as oil, grease, wax, etc. Wiping a surface with an organic solvent may seem like a great idea, but these solvents may dissolve contaminates from rags and deposit them on the work surface where they can prevent epoxy adhesion. This is not a good practice for surface preparation. Silicone is a well-known mold-release agent and incidentally an ingredient in many home laundry fabric softeners. A surface can get contaminated by the silicone that the organic solvent extracts from a wiping rag. Many organic solvents can dissolve the man-made fibers found in rags. An acetone wipe down can deposit plastic on the surface you are trying to clean. These dissolved plastics can act just like a mold release, which is the opposite of surface preparation for good epoxy adhesion.

Solvents are bad news 

In  a pro shop I see very very little solvent used for wipe downs   

Solvents leave behind to many contaminants 

as a experiment wipe down your car windshield with solvent .., it will dry off as a streaky mess

repeat with water and it will be perfectly clean 

 

 

  • Like 2

Share this post


Link to post
Share on other sites

We use water, vinegar(epoxy cleanup), simple green solution (butyl cellosolve), metho(denatured alcohol), and occasionally acetone. 
 

All very clean solvents. Absolutely no tack rags. Spray gun air(clean) and good vacs. 
 

No need for the 80’s autobody shop stench. We primarily use epoxy. I got sensitised to styrene(poly resin & filler) back in 2000 building a poly mold for a 40’ racing boat. My goatee itches within seconds of smelling styrene ever since. 

Share this post


Link to post
Share on other sites
On 12/17/2020 at 8:56 AM, cyclone said:

Regarding acetone- this comes from WEST 

There is no good reason to wipe a surface with an organic solvent unless there is evidence that an organic contaminate is present on the surface. We are all familiar with solvents like acetone, lacquer thinner and proprietary mixtures like DuPont Prep-Sol™ formulated to remove specific contaminants. Most solvents of this type will remove organic contaminants such as oil, grease, wax, etc. Wiping a surface with an organic solvent may seem like a great idea, but these solvents may dissolve contaminates from rags and deposit them on the work surface where they can prevent epoxy adhesion. This is not a good practice for surface preparation. Silicone is a well-known mold-release agent and incidentally an ingredient in many home laundry fabric softeners. A surface can get contaminated by the silicone that the organic solvent extracts from a wiping rag. Many organic solvents can dissolve the man-made fibers found in rags. An acetone wipe down can deposit plastic on the surface you are trying to clean. These dissolved plastics can act just like a mold release, which is the opposite of surface preparation for good epoxy adhesion.

One stupid sim-le question. Who uses random cloth objects (some that wen through the laundry) for wiping anything to be bonded? That is utter nonsense.
You use clean brand new paper towels.

Solvents are a necessary part of the equation in some circumstances. Epoxy bonding to teak for instance. It works.
Removing mould wax.
Cleaning tools. Or do you want to throw your bubble busters out?

Removing varnish or paint strip residue. That is a solvent job. And guess what--you have epoxy repairs to do following that. Handling solvents safely and using them effectively is part of getting work done right,

If you really want to do a proper composites job, learn aerospace. Almost no boat will pass those requirements. And yet most boats work. Go figure...(most...there is that problem!).

Do you like chip brush hair in your job? I don't. Use a good brush. This means cleaning it with acetone and drying it.
If you REALLY want to get picky though, go learn how to do composites from the aerospace guys. Most boats would fail on multiple accounts...

Share this post


Link to post
Share on other sites
On 12/17/2020 at 3:06 PM, slug zitski said:

Solvents are bad news 

In  a pro shop I see very very little solvent used for wipe downs   

Solvents leave behind to many contaminants 

as a experiment wipe down your car windshield with solvent .., it will dry off as a streaky mess

repeat with water and it will be perfectly clean 

 

 

You know why the windshield  anecdote is total baloney misleading and not helpful.

Share this post


Link to post
Share on other sites

Oh and by the way...acetone comes in different grades. When you buy it in 55 gallon drums, most shops buy "technical" grade. LAb grade, reagent grade---those are mega$$$. TEchnical grade may have a certain amount of benzene in it -- and water. Of course once you open an acetone container it takes up water vapour anyway. That's part of why it is so useful. It's a ketone. That's why we love it. Does things aliphatics don't do.

Share this post


Link to post
Share on other sites
On 12/17/2020 at 7:56 AM, cyclone said:

Regarding acetone- this comes from WEST 

There is no good reason to wipe a surface with an organic solvent unless there is evidence that an organic contaminate is present on the surface. We are all familiar with solvents like acetone, lacquer thinner and proprietary mixtures like DuPont Prep-Sol™ formulated to remove specific contaminants. Most solvents of this type will remove organic contaminants such as oil, grease, wax, etc. Wiping a surface with an organic solvent may seem like a great idea, but these solvents may dissolve contaminates from rags and deposit them on the work surface where they can prevent epoxy adhesion. This is not a good practice for surface preparation. Silicone is a well-known mold-release agent and incidentally an ingredient in many home laundry fabric softeners. A surface can get contaminated by the silicone that the organic solvent extracts from a wiping rag. Many organic solvents can dissolve the man-made fibers found in rags. An acetone wipe down can deposit plastic on the surface you are trying to clean. These dissolved plastics can act just like a mold release, which is the opposite of surface preparation for good epoxy adhesion.

that's why when I wipe down, it's with cheap, white , paper towels....    and I used isopropyl alcohol, when it was still available..

Share this post


Link to post
Share on other sites
5 hours ago, Grande Mastere Dreade said:

that's why when I wipe down, it's with cheap, white , paper towels....    and I used isopropyl alcohol, when it was still available..

If you must use solvent use the double wipe technique 

First wet wipe , followed by a second dry wipe 

solvent is bad news , it has marginal benefits , it’s a health hazard , its a fire hazard and an environmental hazard 

kick the habit 

just say no 

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now