Hi All

I keep banging on about using epoxy primers when using cement based adhesives over anhydrite. I then keep getting asked which ones so I am attaching the ones I have seen to be most succesful. There are others no doubt that I am not familiar with.



There is a thrid one called Isoseal from Flowcrete which I have already attached in this post got probs with rising damp!

By The way. Laybond Products also do a range of adhesives for those who don't want to mix brands. They do this through the Biscem range and the Tecknic range.

Mapei do a two component epoxy primer called Primer MF. Although Mapei say you can use Primer G (synthetic) to prime anhydrite floors.

weber do a 2 part epoxy primer PR301, use it for anhydrite or anything with petroleum in, you have to go on it while its still tacky though

weber PR301 - Weber, world?s leading manufacturer of industrial mortars for the facade, tile fixing and construction markets

Originally Posted by penkhull

weber do a 2 part epoxy primer PR301, use it for anhydrite or anything with petroleum in, you have to go on it while its still tacky though

weber PR301 - Weber, world?s leading manufacturer of industrial mortars for the facade, tile fixing and construction markets

Yes - forgot about that one. The only thing is with it you have to be very careful to open the surface of the screed (should be done anyway) as it is quite high viscosity. I have seen it used several times - only seen one problem where it was roller applied over a completely unprepared screed........mud, paint, mortar and all. It did not stick.

Originally Posted by matt257

Mapei do a two component epoxy primer called Primer MF. Although Mapei say you can use Primer G (synthetic) to prime anhydrite floors.

I would not personally use an acrylic unless I was using a gypsum addy or at least a hybrid. If all is perfect it should be ok but I have seen far too many failures to be comfortable. Acrylic is just not robust enough IMO.

Have not seen MF used before so cannot comment

With epoxy primers are they thin to soak in or do they just lay on the surface??

The stay on the surface

Sticks well then

Originally Posted by whitebeam

With epoxy primers are they thin to soak in or do they just lay on the surface??

It depends on the polymer content but the ones I use are generally too thick to penetrate the surface without dilution so I tend to dilute 1:1 with water. The water encourages the primer to get further into the screed but as epoxy uses the water to cure it does no real harm in terms of moisture. If anhydrite, the surface needs to be sanded which helps open it up and allow good penetration anyway.

if the surface is non porous then they will tend to sit on the top and you would need a high tack system. I don't like these much as they do not form a very strong bond. In the case of non porous I would probably go SBR or Neoprene.

So there water based then, the problem is knowing what substrate your dealing with at the time.

I might need your mobile sometime Alan

A distress call

Originally Posted by whitebeam

So there water based then, the problem is knowing what substrate your dealing with at the time.

I might need your mobile sometime Alan

A distress call

07545 932723 - no stalkers please......