What you should know about High-Pressure Laminate (HPL) guitars

What you should know about High-Pressure Laminate (HPL) guitars

HPL, or High-Pressure Laminate materials are becoming more commonplace in guitar construction. Martin Guitars, in particular, have a line made partially, or almost completely, from HPLs. 

As a guitar construction material, there are a lot of advantages. But, in order to go into this with your eyes open, you should be aware of one disadvantage. 

Check it out…

Nasty Acoustic Guitar Side Cracks

Nasty Acoustic Guitar Side Cracks

This guitar's see better days. You can see a couple of nasty cracks along the shoulder. They begun at the preamp cutout and because of the tension on that area of bent wood, they easily spread as the centre 'relaxed' while the edges stayed in place, bound to the top and back. 

Someone has had a go at repairing this damage already. The previous repairer tried using fibreglass and some mesh tape to secure things. A brace was added near the preamp cutout to reinforce it but that and the fibreglass weren't enough. The arrow shows where that brace has broken. The crack's back.

End-Block Crack Clamping

Cracks are never fun. This one's in an awkward spot, too. It was happy to close up relatively easily but it's a tricky location for clamping. 

Time for some out of the soundbox thinking (see what I did there?).

Side crack at end-block

Side crack at end-block

Cutting clamp to side contours

Cutting clamp to side contours

Cutting a block to match the curve of the guitar side in this area was an easy enough job. Now, I had my clamping caul and just needed a way to clamp. I drilled a hole through the caul. This allowed me to feed a bolt through the guitar's end-pin hole and through the hole in the caul. Snugging up the bolt pulled the caul in, closing up the crack.

Crazy block-clamped side

Crazy block-clamped side

Now, to the completely honest, I did add a long, sash-type clamp to give a little extra pressure to be completely sure about this. You can't put too much pressure on with that, though, as it'll start crushing things if you're not careful. The extra helping hand my bolt-clamp gave was just what the doctor ordered in this case. 

Oh, incidentally, that caul is lined with cork and then packing tape. Its slick surface means the glue won't adhere to it. Otherwise, after this repair was done, I'd have a completely new, Caul-Glued-To-Guitar-Removal-Repair to contend with. 

Jack On The Rocks

semi acoustic guitar side repair

It's great having a guitar at a party. Everyone's singing and you're playing and the beer is flowing and—yikes!

Sometimes guitars can party too hard. 

This little semi-acoustic got a bit of a smack as the good times rolled. It was fitted with a side-mounted output jack and it landed (quite neatly, really) on it. The jack disappeared into the guitar and left the side and finished crushed. This image was taken after I'd pulled it back into some sort of shape. 

If this guitar was a super expensive thing with huge sentimental value, we might be looking at an correspondingly expensive side-repair. Sometimes, however, that's not warranted and all that's needed is to get the thing playing again with as little fuss as possible. The easiest/cheapest way of sorting this one is to make the damage good, enlarge the hole and mount the jack on a Les Paul-style plate.

fix guitar sides and jack
guitar repair side damage

The crushed wood had become quite flexible and trying to enlarge the hole in that damaged material would have caused messy chipping and tear-outs. That's not the way to go. I wanted to saturate the area in water-thin cyanoacrylate glue to harden it but even after poking it roughly to shape, the damaged area was still below the surface level and was pretty flaky and messy. 

Enter the Mystery Invention that I teased you with on Facebook and Twitter last night. 

I fished a hefty bolt through the F-hole and gently snugged up a nut on it. This pulled the crushed wood back into something close to its proper shape. I loosened off, saturated the area with super glue and retightened the nut. Incidentally, that white 'washer' you see is a piece of teflon. There's a corresponding piece on the inside too. The glue won't adhere to this and I'm not really keen on ending up with a honking great bolt glued in the jack-hole. The shaft of the bolt doesn't contact the edges but I was very careful to avoid any glue squeeze out contacting there too. 

guitar jack socket repair

Once it's dry, I can enlarge that hole more cleanly. A little, basic, touch-up and clean-up and the jack plate can be installed. This guitar is ready for the next party. 

Super-involved repairs are justified in many cases but, sometimes, quick and easy is the way to go.

Even quick and easy should be done properly, though.