# Biscuit or glue joint



## Ghidrah (Oct 21, 2008)

It's my 1st time in the bit forum, here goes. Normally I wouldn't hesitate using biscuits on exterior projects painted or stained especially when the lines are vertical. I've been using Gorilla glue on exterior items with (to date, no item over 2 yrs) success. I have tons of big honkin horizontal trim sections of fir, most of the items are multiple glue ups 2 to 3 for width and 2 for depth. 

The width glue ups are my concern. I'm pretty sure the biscuits can be hidden in the moldings profile.

Here are the prevailing conditions the place is on the ocean, about 100 ft off the surface, and always hammered by wind rain and salt.

Does anyone here have experience with the use of glue joint bits for exterior projects? 
Any idea how they'll hold up compared to biscuiting?


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## Ghidrah (Oct 21, 2008)

No help? Oh well I guess I'll stay with biscuits.


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## dovetail_65 (Jan 22, 2008)

Ghidrah said:


> It's my 1st time in the bit forum, here goes. Normally I wouldn't hesitate using biscuits on exterior projects painted or stained especially when the lines are vertical. I've been using Gorilla glue on exterior items with (to date, no item over 2 yrs) success. I have tons of big honkin horizontal trim sections of fir, most of the items are multiple glue ups 2 to 3 for width and 2 for depth.
> 
> The width glue ups are my concern. I'm pretty sure the biscuits can be hidden in the moldings profile.
> 
> ...


If you can use the glue joint it will be much stronger than the biscuits. The biscuits in your application sound like they are mostly for alignment. The glue bit and resulting profile increases the glue surface greatly making the joint much, much stronger than just adding a biscuit. 

The glue joint bit is going to be more work and probably take you longer than using biscuits, especially if it is your first time using the glue joint bits.

This is my experience and not based on scientific tests comparing the strengths.


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## Ghidrah (Oct 21, 2008)

Alignment is also an issue here to minimize any extra sanding prior to running them through the molder, I have had success with biscuits in PT lumber where they were subject to weather extremes, (water, snow and ice) arbors, flower boxes etc where nails and screws couldn't be used. My impression was that it might have something to do with a horizontal cut lines ability to shed water better than a vertical cut line.

I was thinking of a reversible glue joint, maybe there's a way to incorporate both into the same project.

Its more important for this work to remain stable, the original work is around 150 yrs and the trim lumber for certain items used for this building back then is 11 3/4" wide and 2" thick.


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## Mike (Nov 22, 2004)

Mouldings are one area where a pin nailer really excells. There is no beating a mechanical fastener for holding and still being able to dis-assemble if needed. The holes are so small that you dont need filler, and they are available in lengths up to 2". Just something to consider.


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## dovetail_65 (Jan 22, 2008)

Personally I do not use biscuits or reversible glue joints to join the lumber into larger pieces. Just lumber jointed correctly and Titebond III. 

I do not like the Gorilla glue very much. I have used the Titebond III for many application since it was introduced and have had no problems on any exterior work at all.


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## Hamlin (Dec 25, 2005)

I have to agree with the use of the glue joint. However, these take time to "align". Setup blocks work great for this. As mentioned, they offer more glue surface.

If you intend on using "pins", and if this is for external. May I suggest using stainless steel pins. They are more expensive but, you won't have to worry about any type of moisture hurting the pins. (They don't rust).


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## Ghidrah (Oct 21, 2008)

I'm not sure about "pins", I have finish, brad, 6&8 penny common&box nailers and spikers. In this area, all exterior fasteners must have heads. The original fasteners are cut nails and have erupted through the hundred years of paint. 

No question, SST is the only way to go here, too much wind and salt water. For most of the exterior things I do I use Titebond, however Titebond doesn't have a winning record in WoodsHole so I'm giving the ape a try.

The posts I'm currently replacing were hollow octagons, 4 hollow Fir posts holding up a massive 30 +' long porch roof, so far the 2 inner posts weren't supporting anything, they were rotten nearly a foot above the granite slabs they sat on. 

As of today I have 2 4X4 Fir posts anchored top and bottom and 6 of the 8 octagonal pieces glued, nailed and clamped around the 4X4s. I didn't bring enough clamps, as nice as the select fir is, it still rolls and hooks.

The posts and octagons are sitting 3/4" and 1/2" off the granite


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## Hamlin (Dec 25, 2005)

Hi,

"pins" = nails or brads. You may want to consider screws countersunk with a plug to cover the hole/head of screw.


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## Ghidrah (Oct 21, 2008)

I thought about screwing, but most of the woodwork fasteners are cut nails, even though many are still sub surface, they're easy to find, (rust bleed through) at the moment I'm leaning toward SST ring nails, both the Makita AN611 and the Hitachi have depth adjustment.

Today I got the last 2 pieces of the octagonal post in. Unfortunately while I was clamping pushing and shooting them in I accidentally bumped my head up against the post, 2 lines of gorilla glue 3 1/8" apart from forehead back. Wifey will have a field day with this one when she gets home.

I began pulling off the fascia/eave molding today, the center 4X12 fir beam is hollow, my wonder bar pushed through it while prying, a solid 2 foot wide black wave of carpenter ants poured out of the damaged area.


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## Hamlin (Dec 25, 2005)

Hi Ghidrah,

I hope that you intend on digging a bit deeper into that damaged area. Best to find any and all damage and get that taken care of before something happens. 

I mentioned the screws for the reason of, if you have a plug cutter, you can hide the screws completely. Just need to use the same type of wood though.

I'm a firm believer in the phrase, "glue it and screw it". I do use brads or small finish nails from time to time but, nothin beats good glue an stainless steel screws... an lots of clamps. 



> Wifey will have a field day with this one when she gets home.


Just give her that deer in the headlight look and say "huh".


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## Ghidrah (Oct 21, 2008)

Hey Hamlin,
Today the Terminex man showed up to spray, "So where's all the ants?" SMACK, SMACK ,SMACK, lots of them came out to play and show off their eggs after the beams began vibrating violently. Once the Bugman left the dead man went up and I got to hackin and slashin. I cut out the middle section and was amazed at all the stuff in there, I may keep 1 or 2 of the bent cut nails. 

You could see where successive period repairs were muckled into the older work, Oldest materials pre dimensional lumber, (real 2X Fir stock, late 60s early 70s 1 3/4" pine and probably early 80s at 1 5/8" pine. Padding all over the place to make line.

I got 1 section of PT back in, before a massive clean-up, I don't have much room with all the staging and work station. It's difficult to decide how deep to dig, when the surface mat is solid and tight, so far all of the damage is within the padding areas. As I move around the corners of the porch I may end up replacing more framing, that's where the downspouts from the 2nd floor roof gutters and AC drain tubes empty. To date I'm thinking the nest may well be in the south wall. The building is balloon framed to the 2nd floor.


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## Hamlin (Dec 25, 2005)

Hi Ghidrah,

It sounds like you're making progress.


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## Ghidrah (Oct 21, 2008)

Yeah some, the beam is in all the molding has been removed from the front of the roof but I discovered more rot on the corner post, (also hollow) as I pulled the last bit of molding off the corner the upper south section of the post came off with it.

I'm having a real hard time figuring out how this roof has stayed up. It's possible the roof ceiling joists are cantilevered off the house floor joists. I tried looking in with the flashlight but couldn't see, I probably should have taped it to a pole.


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