SPF Dimensional Lumber Mold: Laminated 2″ x 4″ x 8 ft

February 12, 2024 Jon Off CNC Router, CNCROi.com News, Wood Products,

SPF dimensional lumber mold making using laminated 2x4s is a very efficient process, both material and process wise, as it’s widely available in addition to being a softwood.

CNCROi.com has made tons of molds through the years, the material we use depends on the final application that the mold will be used for, in some applications, hardwood is required, others, it can be delrin or other tough plastics and yet others, softwood is more than fine.

For this SPF dimensional lumber mold, I used 2″ x 4″ that were 8 ft long, so they all had to be cut in half in order to make the mold to the right size.

I add pencil marks to the surface as it’s hard to tell when everything is completely flat, to be laminated propertly, as such, when the pencil marks are gone, that means everything is flat and can be properly adhered together.

When it comes to making lots of dust with our CNC router, it really doesn’t matter what we feed our machine, it eats it all up but deep pockets are always a challenge, mold or otherwise, because there is a lot of leverage put onto the tip of the bit relative to the overall length.

After I flattened both sides of the 2″ x 4″ that was earlier cut in half, it’s time to glue or laminate it all together to make a solid block from which the SPF dimensional lumber mold will be produced using CNCROi.com‘s industrial CNC router.

Although everything is technically dry after 24 hours, I generally give the whole block, regardless of size or what will be carved out of it, a few days to thoroughly dry as the last problem I need when making these, is parts flying off due to the stresses put onto and into the laminated wood or worse, bits breaking because there was a little too much give when carving it out using larger diameter bits at CNCROi.com.

Once the SPF dimensional lumber mold is dry, it’s time to switch gears and flatten the top and bottom yet again, if you are keeping track, it means that basically, every side of the original 2×4 is cleaned-up and made flat and parallel during the mold making process before I even make the first cut into the solid block.

I’ve been laminating wood of all types of species for several years now, each time I do this, I learn how to do something a little better than the previous time and as a result, the results get better and better.

The table vacuum system is more than powerful enough to suck the entire block down onto the MDF bed of CNCROi.com‘s CNC router but I still screw in a few of the corners right onto the bed just incase, as there is a lot of stress put onto this piece of laminated wood, especially after I carved more than half of it away while making it into a SPF dimensional lumber mold.

Unlike hardwoods, softwoods can be stringy when carved out, not a big deal generally but they can actually wrap around the bit and when something is spinning at 15 000 RPM, actually cause quite a lot of forces around the bit to stress it until it actually breaks, so I pay special attention to this if it builds-up too much as yes, I have broken large diameter bits from this before at CNCROi.com.

The first pass, after the initial clean-up on both sides of the SPF dimensional lumber mold, is using a half inch roughing bit in order to quickly remove waste material that has no reason of being part of the mold, the secondary process is using a finer bit in order to increase the resolution of the overall mold and clean it up.

I want to remove as much material as possible using the larger diameter roughing bit because this is what will save me a lot of time with the finer bit for clean-up and reduce the chances of it breaking on me during production but regardless, while making this SPF dimensional lumber mold, I did break a ball nose bit during the clean-up process from the stresses involved with making this mold at CNCROi.com.

Whether I’m laminating and forming Maple, Oak or in this case, Fir, the results are always spectacular, it is easy to work with softwoods like Poplar because there is less stress put on the bits as they chop through it but hardwoods are less stringy.

Using the roughing bit, you can clearly see how clean the overall lamianted 2x4s become, it’s quite a solid piece of mold by the time I get to this stage, the glue is more than dry enough and the bonds between everything are very strong without any voids or things that want to fall apart.

Several passes are required in order to complete the SPF dimensional lumber mold using the roughing bit, only one pass is required thereafter with the ball nose to clean everything up to the final resolution required by the CNCROi.com customer.

In the image below, you can see and start to appreciate just how much work the small ballnose bit does on this SPF dimensional lumber mold, very fine steps and a very solid machine make sure nothing moves except the bit and the results are spectacular.

There is a lot of sawdust created during the production of this SPF dimensional lumber mold, the bigger and deeper the mold, the more wood is required and generally, the more wood is removed during the production of a mold.

There are endless applications for 2x4s, from custom name badges to industrial molds, it’s really quite a wonderful material to work with for a wide variety of applications and needs.

It’s quite a difference between the roughing and cleaning process when it comes to making the final SPF dimensional lumber mold, overall, the entire process is rather fun and I really enjoy doing this type of work at CNCROi.com because there is so much that happens and a huge transformation in the solid block I made.

The bonus of making these SPF dimensional lumber molds is that it’s very easy to sand and add bondo to, as well as a host of finishing methods from primer to liquid resin, it’s just such a diversified material production wise.

Take a look at these close-up pictures of the finished SPF dimensional lumber mold, the resolution is amazing and the final mold just needs a light sanding and clean-up for voids caused by knots and such before going into final production by the customer for their application for this SPF dimensional lumber mold.