3M High Strength Repair Filler

[Namrups]

3M High Strength Repair Filler (HSRF) has been the go-to filler for a number of different applications by a number of respected builders on the forum. Since the covid epidemic HSRF has become impossible to find. Has anyone run across a substitute that offers similar properties?

[Peter Ross]

3M Marine Premium Filler is a very good alternative, vinylester and available from multiple sources. Well worth the price.

https://www.defender.com/product.jsp?id=3967173

[Kbl7td]

Just make your own. Epoxy+glass fiber or micro balloon or cabosil depending on the project.

(US composites) is my go to.

[Jeff Kleiner]

3M Marine Premium Filler is a very good alternative, vinylester and available from multiple sources. Well worth the price.

https://www.defender.com/product.jsp?id=3967173

This is a shaping filler, not a structural filler like HSRF. They are not used for the same purpose.

Boatstore.com shows both quarts and gallons as available but since I haven't purchased any for a few months I can't speak for the accuracy of the website.

https://boatstore.com/marine-high-strength-repair-filler-quart

Jeff

[GoDadGo]

Have you considered using Evercoat Fibertech?

https://youtu.be/tY3E0ztz8SY

We used it the door horns near the cowl on my MK-4 since it is a rather hearty product.

https://youtu.be/6UK6K2jcwTU

Even though it wasn't needed for my issue it gave me confidence in building up the tip of the door before floating it with Evercoat Rage Gold.

NOTE:.. I consulted with Jeff Kleiner before taking this action and he thought it was overkill.

[Peter Ross]

This is a shaping filler, not a structural filler like HSRF. They are not used for the same purpose.

Boatstore.com shows both quarts and gallons as available but since I haven't purchased any for a few months I can't speak for the accuracy of the website.

https://boatstore.com/marine-high-strength-repair-filler-quart

Jeff

Very true. The 3m Marine is a very robust filler.

[Namrups]

Thanks Jeff. I ordered a quart. Waiting to get the confirmation and shipping info.

Update: Order was cancelled due to product being out of stock and unknown restock date.

[Kbl7td]

Thanks Jeff. I ordered a quart. Waiting to get the confirmation and shipping info.

Update: Order was cancelled due to product being out of stock and unknown restock date.

You’re going to save a ton making your own…

[Namrups]

Just make your own. Epoxy+glass fiber or micro balloon or cabosil depending on the project.

(US composites) is my go to.

What's your formula?

[Kbl7td]

What's your formula?

I just eyeball it. Mix your epoxy as you normally would, 4,6,8oz. Whatever you need. Then add the cabosil to your consistency preference and mix, generally a peanut butter feel. You can make it as runny or solid as you want. Cabosil is very very hard when cured so not recommended for body fill in totality, mainly structural areas say where you want to fill in curves before laying glass (glass doesn’t like to bend). 3d spheres are better for body fill, you’ll have to mix in a lot of spheres to get a nice consistency, sort of like cold syrup. It sands easily. Epoxy and 1/16 fibers or 1/4 fibers is going to give you the epoxy strength with tensile strength. It should lay fairly flat and sand easy.

I would use cabosil mix for deep voids in body seams, then the microspheres over the top to sand. Bang for your buck this is it. Then you can rage gold to perfect everything.

How do I know this stuff? The RCR SLC and they’re associated cars, tons of body work, tons of customization. Makes the FFR cars look like a Lego set.

One area I plan on using the cabosil is the front hinge spacers. I see a lot of talk about adding some space to the front hinge to get it to open properly. This is a perfect place to mix up some cabosil and epoxy in a plastic sandwich bag then place it in between the hinge and body. Gives you perfect conformity. When dry take off the back and now you have a perfect spacer of hard epoxy to now epoxy to the inner body so the hinge mount stays true and flat.

[Namrups]

I just eyeball it. Mix your epoxy as you normally would, 4,6,8oz. Whatever you need. Then add the cabosil to your consistency preference and mix, generally a peanut butter feel. You can make it as runny or solid as you want. Cabosil is very very hard when cured so not recommended for body fill in totality, mainly structural areas say where you want to fill in curves before laying glass (glass doesn’t like to bend). 3d spheres are better for body fill, you’ll have to mix in a lot of spheres to get a nice consistency, sort of like cold syrup. It sands easily. Epoxy and 1/16 fibers or 1/4 fibers is going to give you the epoxy strength with tensile strength. It should lay fairly flat and sand easy.

I would use cabosil mix for deep voids in body seams, then the microspheres over the top to sand. Bang for your buck this is it. Then you can rage gold to perfect everything.

How do I know this stuff? The RCR SLC and they’re associated cars, tons of body work, tons of customization. Makes the FFR cars look like a Lego set.

One area I plan on using the cabosil is the front hinge spacers. I see a lot of talk about adding some space to the front hinge to get it to open properly. This is a perfect place to mix up some cabosil and epoxy in a plastic sandwich bag then place it in between the hinge and body. Gives you perfect conformity. When dry take off the back and now you have a perfect spacer of hard epoxy to now epoxy to the inner body so the hinge mount stays true and flat.

Do you have any specific suppliers? Having worked as a R&D technician in a silicone chemical plant, mixing up my own batch is nothing new to me. Just need to find local suppliers of the inputs. Any specifics on the inputs your using would be helpful.

[Kbl7td]

Uscomposites.com great prices out of west palm, lots of boats built down here. Have everything you need, just get to know the website, take a minute to navigate. They’ll ship it out in a day or 2.

Check this site too… https://forums.iboats.com/threads/wh...butter.315119/