Problem mounting canvas prints on Gatorboard

[dajaka]

I've recently been having a problem mounting canvas prints on Gatorboard. I've done this for a few years with no problems up until now.

I print and coat my canvases (BC Lyve and Glamour II) and then after letting them dry for a few days mount using Miracle Muck on 1/2" Gatorboard using a vacuum press.

The last few prints I've done have resulted in what looks to be oval bubbles in the prints about 1.5" wide with anywhere from 4-10 instances in the print.

The defects are however, not bubbles. They are slightly raised areas but are as hard as the surrounding parts of the prints. They don't show up until the prints are dry. They look fine when I mount them in the evening and then the defects are visible when I look at them the next morning.

The only thing I can think of is that perhaps this is a defect in the gatorboard foam interior, with maybe it being patched during manufacturing? I buy them by the case and
I have had these boards for a while. I can't imagine that would matter.

I've attached a photo showing what this looks like.

If anyone has any ideas, I'd love to hear them. This is very frustrating.

Thanks.

[BillK]

One way to tell, since the print appears to be ruined anyways.
Cut through the lump (print and gator)and look at the cross section. You should be able to tell
whats causing it.

[PeterAit]

I don't suppose it has something to do with the varnish? Seems unlikely, but might be worth looking into.

[Paul2660]

I assume since you have let the Muck dry, when you are using the Vacuum press, you have heat on?  If so, you may have encountered a flaw, weakness etc in the actual gator since the bump is hard.  I would also like to know what the core of the bump looks like as if it's gator, then it's probably heat somehow causing it.

I mount a lot on gator, both 1/2 inch and 3/8", but I only do wet mounts.  Never have seen this before. 

I also use muck, it also may be that Raphel's has reformulated muck? 

Paul

[dgberg]

No need for that vacuum press with MM, just an unnecessary extra step.
Spread your Muck lay print on substrate and brayer any bubbles out then trim.
As mentioned it may be a substrate defect that shows up after your done?
We do hundreds but I have never seen this with our process.