Messing with Marine Tex

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.


Moderator Emeritus
Jul 30, 2009
Vessel Name
Skinny Dippin'
Vessel Make
Navigator 4200 Classic
Hey Y'all,

I have about 20 vertical screw holes in my cockpit that need filling. Marine Tex would be perfect since I can't seem to get West Systems thick enough for vertical holes. Last week I bought some for a different project (scratches in dinghy bottom) to just see how it worked and found it to be a real mess to work with. Getting it out of the little glass jar and mixing it with the hardener was a huge pain. the stuff is so thick that it sticks to everything. I was using one of those black stir sticks from West Systems and a piece of cardboard to try and mix it on. It suck to the stick and would not want to come off the stir stick easily (where I wanted it to be) and basically fought me the whole time. Any tips on working with this stuff?

Once I finally got some mixed, it worked well filling the holes, but dag-gum, if there is an easier method to mix it, I would love to hear it.

WEST G-10 in a caulking tube might be your answer.
Last edited:
If you can get to the underside, you can tape up the holes and then the epoxy doesn't need to be as thick. The tape needs to seal REALLY well, though, as thin epoxy will get through just about any crack.

Alternatively, you can also squirt some hot glue or something else down in the bottom of the hole to seal it off, then top off with epoxy.

I have used both of these methods in the past.
Last edited:
It’s WEST Six 10 not G10 that comes in a caulking tube. Sorry.
I use this stuff for filling screw holes and other little cracks. I mix it up and then use a craft syringe to squirt it in neatly. It's liquid enough too when first mixed that it lays down nicely into screw holes or cracks. The only problem is that while it goes on bright white, in my experience it quickly turns an ivory color, but it's got excellent adhesion and it's almost as hard and durable as the original gelcoat. Once you lay a very fine line on a crack or ding or fill a screw hole, you'd need a hammer and chisel to get it off.

(Sucking up a puddle of it into a craft syringe is not that easy, you have to go really slowly, but that's a nice neat way to apply it.)


  • 81xuI+j4iJL__SL1500_.jpg
    115.4 KB · Views: 116
That Loctite stuff is great. I liked this JB Weld product too.

Using one of those syringes makes the job easy and more thorough, though I did do a snap hole with the Loctite right out of the tube.

Timely thread as I have some of this type of work coming up on the Whaler.
Last edited:
Practice, practice, practice. Now that you have met the enemy you know how to handle it. Use gloves, disposable EVERYTHING, paper towels and rags.

If it weren't for Marine Tex I wouldn't have a boat.
We used 3M Filler. Think it’s an epoxy.

We used it as the yard where we were on the hard used it extensively. It’s green in color and easy to use. We filled several hundred holes in our cabin over 10 years ago and not one hole has been a problem since.

Oh I’ve got a question that Parks or sombody probably knows .... is Marine Tex and JB Weld essentially the same? I suspect JB has a filler or similar whereas MT does not but it’s pure speculation.
Last edited:
a bunch of popsicle sticks or wood shims split lengthwise one for each jar and other to scrape off the stuff. Scoop equal size blobs of each and scrape off with the seconds clean sticks. Stir with another clean stick and you are all set.

Filling blind holes can be difficult so push it in with a toothpick or it will be air bound. Some tape over the hole will ease clean up
I just grab 2 flat blade screwdrivers, paper towels, marine tex, toothpicks, and a piece of cardboard.

Big screwdriver opens paste and scoops out 5/6 of necessary filler, little screwdriver dollops hardner, the other 1/6.

Wipe off litttle screwdriver, put away. Mix batch with large screwdriver and apply if right tool, if not, scrape off with right tool or toothpick. Wipe clean, put away.

Use toothpicks to fill holes by dabbing or get a wad and shove in hole, break off and cut below hole level with razor knife. Top off hole with another dab.

Leave toothpick on whats left of marine tex on cardboard for about 5 hrs to see how hard and strong that batch was.

Find marine tex much easier to use than 2 part epoxy liquids...but it is way more expensive.
It’s WEST Six 10 not G10 that comes in a caulking tube. Sorry.

I have an unopened tube of this. I bought it to fill the snap holes on the deck from old covers we don’t have. But I wasn’t sure if it will do vertical holes. I can’t get to the back, so it is going to be a bit of a trick which is why Marine Tex looked appealing.

Thanks for the tips yall.
I noticed Mr. kt mentioned hobby syringes (post #5) and the inherent difficulty in filling them. I have found that rather than attempting to suck up the "whatever" is much easier to pull the plunger out of the barrel and pour or spoon the "whatever" into the open barrel. When filled to your liking, simply push the plunger back into the barrel and start your applications. Yes, you WILL get some spewing out of the nozzle initially but that is easily wiped off to start afresh.
Thing with trying to get epoxy thick enough is to use the correct additive for the correct usage.
Question for you, the holes you want to fill are in your cockpit but in what material? FB? Wood?

Thing with trying to get epoxy thick enough is to use the correct additive for the correct usage.
Question for you, the holes you want to fill are in your cockpit but in what material? FB? Wood?


They are in fiberglass. I have 105/205 plus 410 faring and 403 adhesive currently in my kit.
I use 406 (silica) as a multi purpose filler and have got good results. For one dose of epoxy/hardener I use 2 to 3 table spoon of 403 to get a thick enough consistency. In wood I use wood flour of the same wood.
I use EXP system epoxy but should be the same with West System.


I use West epoxy all the time. I can thicken it enough to hold on vertical surfaces. I use 404 if I think it needs more strength. Just keep adding your filler until it gets thick enough. If I use it really thick, I usually brush some unthickened epoxy on first to help the thick stuff bond to the fiberglass.
Hull and deck putty. Fills holes , cracks,fairs. Use above or below waterline. Polyester based, just like your fiberglass boat. Many companies make it.
The first question might be “do i need to sand/fair the cured patch?”
If so definitely avoid the jb welds, marine tex and the likes. With the right additives West will do anything y want. And per above post, if above water line consider polyester, even one part stuff
I use a piece of wood that I wrap in aluminum foil as a mixing board. I then use popsicle sticks to get a blob of MarineTex and pour a bit of the hardner on it. Mix, and then use a clean popsicle stick to apply. Then use another popsicle stick to scrape flush.
It hardens like a brick. When we repaired over 60 holes from prior owners art and decorating, we put painters tape around each hole first. This made clean up easier and fast. Do not leave the MarineTex too proud as sanding it proves a lot of work.
Just shoot some 5200 on the holes and be done with it! :hide:
First, use what ever you are comfortable with.

Second, there are two different West additives, I don’t remember the numbers, one is off white, it’s easy to sand but has no strength. The other looks light brown and is for applications requiring strength but is harder to sand. Both can be mixed so thick that they won’t run. It takes a lot of additive, way more than you think. If you think you put to much additive in, don’t add any epoxy, just keep stirring, it will mix. Put tape on the bottom side of the whole and then fill. Over fill and sand after 4 hours. Better to sand between 4 and 8 hours, after 24 the epoxy becomes very hard. This is true with most any epoxy product.
MarineTex for me has worked well for many repairs/improvements for us and I like that the color is a very close match to our white!
MarineTex for me has worked well for many repairs/improvements for us and I like that the color is a very close match to our white!

That is my thinking too.
I think the WEST Six10 would be the easiest way to get thickened epoxy into small holes. It's thick enough to stay in the holes but I just thought of a reason it might not work for you. It's not white. It's sort of clear amber.

Here is a description of it's properties:

As has been pointed out, it is expensive. The tube is only about half full but that will fill a lot of small holes.

I do a lot of work on my boat with Bondo. Great stuff for cosmetic work, and cheap.

Engineer's Solution:
I would suggest to use a small circular piece of cardboard, just bigger than the hole. Tie a piece of thread through a small hole in the middle, and fold it in half. Push the cardboard through the hole, and use the thread and a toothpick to cover the bottom. Then you can use slightly thickened epoxy to plug the bottom of the hole. Once that has cured a bit, cut the thread, and fill the rest of the hole, using appropriate fillers to make fairing easy.

Complicated, but simple at the same time.
you dont say what you want to do with the holes. If you want to mount something small dry wall plastic anchors with the tops cut off will work.
If you want to fill unused holes for cosmetic purposes it will be difficlut to make them blend in. I had that problem after removing some fish rod holders and just put nice SS round head screws in the holes. Looked fine,
Last edited:

Latest posts

Top Bottom